Sarah and Jamie McCauley are landlords, YouTubers, Walmart pallet flippers, eBay resellers and Amazon product reviewers — and those are just their active streams of income.

The McCauleys make their money by researching what makes side hustles profitable, testing them and teaching others how to do the same on YouTube. The Grand Rapids, Michigan-based couple earned nearly $140,000 from eight streams of income last year, according to documents reviewed by CNBC Make It.

They’re particularly good at two types of gigs, they say: anything involving real estate and their YouTube channel itself, where they share their side hustle exploits with at least 146,000 subscribers.

“If you’re looking to just make some extra money on the side, maybe pay off a credit card debt or pay for a vacation, I think that is doable for nearly everybody,” says Jamie.

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The McCauleys are part of a side hustle revolution, a growing number of Americans who supplement income with multiple jobs. More U.S adults — about 39%, according to Bankrate — have side hustles today than ever before, whether out of necessity, precaution or a desire to increase their earning power.

Ease of starting is at an all-time high: Platforms like Amazon, Airbnb and Fiverr offer instant access to paying customers. But with competition also rising, it’s hard to build a side hustle that regularly brings in revenue.

Make It spoke with a selection of Americans with successful side hustles to learn how they built their businesses, and used them to fund a wide variety of financial goals. Every respondent highlighted four common traits that helped drive their success:

No matter what you sell, you need people willing to buy it. Jenny Woo says her side hustle is successful for a simple reason: She researches her audiences intensely, and tailors her products specifically to them.

Woo is an adjunct lecturer at the University of California, Irvine, a freelance business consultant and the teacher of an online course about emotional intelligence. Her one-woman side hustle, called Mind Brain Emotion, sells 12 different emotional intelligence-themed card games.

It brought in $1.71 million on Amazon last year, according to documents reviewed by Make It.

Woo’s first deck of cards, “52 Essential Conversations,” was tailored toward parents who — like her — wanted to connect with their kids and build their emotional intelligence skills. She joined parenting Facebook groups and observed users’ posting, commenting and liking habits, she says.

After selling $10,000 worth of the game in a 2018 Kickstarter campaign, Woo kept researching. She conducted a survey of her consumers, and learned that “overwhelmed” teachers looking to support children’s social and emotional development made up a significant portion of her audience, she says.

Her second deck, “52 Essential Relationship Skills,” was built for those teachers. It didn’t sell as well as her first deck, but it taught Woo that she could broaden, and combine, her audiences.

Woo applied that lesson to her third game, “52 Coping Skills.” She started with her own experiences working with college students during the Covid-19 pandemic and combined it with her continued research on teachers and parents, she says.

It’s now Mind Brain Emotion’s top-selling game, says Woo.

Woo sells on Amazon, which has a broad reach, to collectively rope in Mind Brain Emotion’s hyper-specific audiences. Tim Riegel’s products have a more singular customer base, so he sells on Etsy, a marketplace known largely for homemade and handmade goods.

Riegel, a full-time general manager at a sheltered workshop, makes firepits from recycled tank ends in Lamar, Missouri, and sells them under the name Mozark Fire Pits. His average product weighs 225 pounds, and sells for $950.

Mozark Fire Pits brought in approximately $202,000 on Etsy last year, according to documents reviewed by Make It. Riegel maintains a 40% profit margin, he says.

Riegel chose Etsy over platforms like Amazon, Wayfair and Overstock because it felt more user-friendly, and a better fit for his personalized products, he says. He also sells on Facebook Marketplace, which costs him more in advertising — but less in shipping costs for customers within a 200-mile radius, he adds.

That kind of platform analysis is valuable, no matter what kind of side hustle you run.

If you sell a service, instead of a good, you might consider platforms like Fiverr and Upwork — popular among photo editors, marketing writers and voiceover artists — or Taskrabbit, known for labor-intensive side hustles like cleaning or repair work.

Or, opt out of those platforms entirely. If your gig is something that many other people also do, try finding marketplaces with more narrow niches like Contently, Skyword or ServiceScape, recommends side hustle expert Kathy Kristof.

“One of the problems I see with a lot of freelancers is that they go to the best-known online platforms … and those platforms are so saturated with people who have been there for, often, decades,” says Kristof, whose blog SideHusl has reviewed more than 500 different side gigs.

No matter your platform, you’ll need to stand out. A good listing can help: clear and concise, written for your intended audience, free of typos, with high-quality graphics and some search engine optimization (SEO).

Becky Powell, a kindergarten teacher based in Beaverton, Oregon, has a side hustle selling worksheets for other educators on an online platform called Teachers Pay Teachers. Many of her worksheets focus on her personal specialty, teaching children sight-reading skills.

Her side hustle didn’t take off until she embraced SEO. When she uploaded her first worksheets, she titled them, “Creating sight words with pattern blocks.” Sales slowly trickled in.

Her husband Jerome, who has a business background, suggested a simpler title, like “Hands-on sight words.” The sight-reading worksheets quickly became her bestselling products, Powell says.

Powell’s store brought in $125,500 in 2022 revenue, according to documents reviewed by Make It. Her husband also sells worksheets on the platform, and they’ve used their combined earnings to fund vacations and pay down their mortgage and student loans, Powell says.

“You have to have passion and knowledge,” she says. “You also have to have a business sense [and understand] SEO.”

Once you gain enough customers, work to turn your sales into positive reviews, so you appear higher in platforms’ search results, Kristof advises. Customer service, prompt shipping and quality control can usually earn you a good online reputation.

The McCauleys have a rule for their ever-changing collection of side hustles: “You either have to be one of the first to get there, or your approach has to be very unique and different to be successful,” Sarah says.

But being first or unique doesn’t guarantee long-term success. In 2020, the couple was early to a side hustle trend: pallet flipping. At local warehouses, they’d buy pallets of returned goods from Amazon, Walmart or Target. They’d unbox the pallets, discover their contents and resell the items for a hopeful profit.

From December 2020 to December 2022, the McCauleys made about $19,500 in pallet-flipping profits, they estimate. Their most popular unboxing YouTube video got 5.4 million viewers, translating to an additional $30,000 in advertising revenue, says Jamie.

Last year, more Americans hopped on the pallet-flipping trend. Pallet prices rose, resale values dropped and a slew of unboxing videos diluted the McCauleys’ viewership. “The pallets became not really worth our time … from the standpoint of time over money,” says Sarah.

Four years ago, the McCauleys would’ve simply moved onto their next side hustle. Now, they’re feeling the strain of constantly building new gigs from scratch, and starting to reorganize their income streams into a smaller number of longer-term projects.

Instead of flipping their current home renovation project in Northern Michigan for a profit, for example — something they’ve done multiple times — they’ll keep it as their own vacation house and part-time Airbnb rental, they say.

“We always knew [side hustling] was going to have an expiration date,” says Jamie. “It’s a young person’s game, to always be looking for what’s next.”

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Almost 60% of the caloric intake of the average American diet is coming from ultra-processed foods, according to a 2017 paper published in the journal Population Health Metrics — and that’s concerning to health experts.

“Ultra-processed foods contain ingredients that we generally wouldn’t find in our kitchen, and they often contain high amounts of sugar and salt,” says Jinan Banna, registered dietitian and professor of nutrition at the University of Hawaii.

“They may also contain additives, and they often are stripped of their nutritional values. So they may have very little vitamins and minerals [and] fiber.”

Eating ultra-processed foods often can lead to a higher risk of developing health conditions like dementia, type 2 diabetes and heart disease, according to doctors in the American Medical Association.

That’s why Banna limits her consumption of ultra-processed foods and encourages you to do the same. Here’s the highly processed food that she never consumes.

“Some [ultra-processed foods] I would never consume, such as soda,” Banna tells CNBC Make It.

“Soda doesn’t have any nutritional value other than just calories in the form of sugar. So they’re empty calories, which don’t give us any of the nutrients that we need.”

When you drink soda, it is digested very quickly and can cause you to feel hungry, she adds, which can lead you to eat more food than you planned to.

Instead of soda, Banna opts for different types of tea and water, still or sparkling.

“Sometimes I drink a cold hibiscus tea. Plain water, of course, is a great alternative,” she says. “Even coffee can be an option, of course, consumed in moderation.”

A recent preliminary study that was presented last week at a meeting held annually for the American Society for Nutrition took a close look at dietary data collected in 1995 from more than 500,000 Americans between the ages of 50 and 71. The data was used to determine if there were connections between dietary choices and mortality rates over the span of almost 30 years.

Out of 124 foods, ultra-processed drinks was the No. 1 food that people who had the highest intake of ultra-processed foods consumed.

“Diet soft drinks were the key contributor to ultra-processed food consumption. The second one was sugary soft drinks,” the study’s lead author Erikka Loftfield told CNN.

Beverages make up a significant portion of dietary intake. So, these types of drinks — like diet sodas and energy drinks — are the processed food that people seem to consume more than others, Loftfield said.

The study also found that the lifespans of those who eat a diet high in ultra-processed foods may be shortened by over 10%, according to CNN.

As a rule of thumb, Banna recommends using the 5/20 method when checking the nutrition labels on the foods you eat.

“You can use the daily value,” she says. “That’s an easy way to know whether the food is generally high or low in a particular nutrient.”

Check the daily value percentages of specific nutrients like sodium, sugars or saturated fat, Banna suggests.

“The idea is, if [it’s] 5% or less, then the food is generally low in that particular nutrient. If 20% or more, you can consider the food high [in the nutrient],” she says.

“So that’s just a quick way to glance at the label and know if a food contains a little bit or a lot.”

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These days, we could do with all the mental strength we can muster. 

Mental strength is the ability to productively regulate your emotions, thoughts, and behaviors, even in the face of adversity. And adversity is in no short supply. If you want to overcome more challenges, achieve more success, experience more happiness and less stress — it takes mental strength. 

After spending decades studying mental strength and interviewing and surveying thousands of people for my recent book, “The Mentally Strong Leader,″ I have good news. The mentally strongest people tend to share certain habits we can learn from. There are patterns I’ve noticed when it comes to what they say (and don’t say) and what they do.

If you always do these eight things, you’re already mentally stronger than most. If you don’t — yet! — you can look to this list as a mini-playbook that will help you level up your mental strength.  

That adage about how you should “leave your emotions at the door” just doesn’t work. If you’ve tried it, you know it’s not that simple.

That said, while mentally strong people are aware of emotions triggered inside, they don’t let those emotions instantly flow through into words or actions. 

They catch their emotions, consider if they’re helpful to express, then decide how to respond. In other words, regarding unhelpful emotions, they catch it, check it, and change it (using the the 3 Cs of cognitive behavioral therapy).

We all contend with doubt. Even the most confident people I’ve interviewed experience doubt. 

Confidence, then, is your ability to manage your relationship with the doubt you’ll inevitably experience. 

The mentally strong have found the right middle ground between overconfident and paralyzed by fear of failure. They acknowledge doubt, but let it sit quietly in the background so they can focus on how they will accomplish something, not if they can accomplish it in the first place.  

Imagine a friend, clearly upset and in need of empathy, was telling you about a relationship they just ended. After listening, would you say: 

“How could you let this relationship fail? It’s all your fault, you jerk!” 

I doubt it. Instead, you might say:

“I appreciate what you’re going through and how much it must hurt. Try not to be so hard on yourself.”

You should take this more compassionate tone with yourself, too. 

When we face setbacks, we often try to go it alone, forgetting that one of the most important things mentally strong people do is to seek perspective and support. 

Know what your “resilience needs” are, and then draw on them. For example, when I experience setbacks, I call a sibling to laugh about it. My resilience need is to tackle challenges with humor, and I know my brothers or sister will recognize the comedy in the situation and make me feel better.

Others might need someone who will just listen, be a shoulder to cry on, or become an advisor. 

Whatever your resilience needs are, identify who in your network can help you in that way, and then call on them at the right moments. Resilience is a team sport.

Mentally strong people don’t get worn down as much by the daily grind. 

Whether or not they realize it, they engage in a combination of gratitude and mindfulness — a practice I call grindfulness. It means being present and mindful enough in daily life to notice the details and show gratitude for the positive aspects of whatever grind you find yourself in. 

For example, say you’re having a tough morning at work. You’re answering a string of emails that came in overnight, and you’re frustrated. But you stop to marvel at the fact that you can type a few words, hit a button, and within seconds, your thoughts are transmitted to someone halfway across the world. Amazing. 

Your appreciation for this mundane detail lifts your spirits just a little, helping your mood. That’s grindfulness. 

Mentally strong people recognize when to let go of preconceived notions. They know when to drop points of view and ideas that are no longer relevant or useful to them. They identify and ditch bad habits that prevent them from moving forward productively. They regularly challenge their assumptions. 

In short, they know they sometimes need to unlearn in order to learn. 

Start by identifying and exchanging your limiting beliefs. What unhelpful stories do you tell yourself that have become ingrained? What unwarranted labels are you applying? 

For instance, you might label yourself as less talented than your peers and tell yourself: “I’m not good enough to get promoted.” Replace those limiting beliefs with empowering beliefs like, “I have all the skills needed to get promoted.”

It takes mental strength to consistently be supportive of others, especially in the face of negativity, when others are doing the easy thing and jumping on the “Complain Train.” 

Even better than generic encouragement or positivity is informed encouragement, which is when you give praise or positive reinforcement that is specific in nature. Doing so shows you took the time and care to indicate exactly what deserves praise and why, making your words feel more authentic and meaningful.

In times of change, you can act like change is something bad that causes pain and requires unwanted effort — like it’s something happening to you. 

Mentally strong people, on the other hand, see change as something positive, a jumping off point that can improve personal and professional fortunes — like it’s something that happens for you. 

You can choose to see change as a personal software upgrade, a catalyst for growth, and another opportunity to exercise your mental strength muscles.  

Scott Mautz is a popular speaker, trainer, and LinkedIn Learning instructor. He’s a former senior executive of Procter & Gamble, where he ran several of the company’s largest multi-billion-dollar businesses. He is the author of ”The Mentally Strong Leader: Build the Habits to Productively Regulate Your Emotions, Thoughts, and Behaviors.” Follow him on LinkedIn.

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Expats in Denmark are among the happiest with their work lives, according to the latest Expat Insider survey from InterNations, the online global community for people who’ve moved abroad.

The Nordic country ranks No. 1 for where people are most satisfied with their jobs, career opportunities and work-life balance, among other aspects.

That’s based on survey responses from more than 12,500 people living in foreign countries and reflects their feelings on four broad categories covering work topics, including their career prospects, salary and job security, work culture and satisfaction, and work and leisure.

Denmark ranks highest for two groupings: work culture and satisfaction, as well as work and leisure.

Some 84% of expats in Denmark are satisfied with their work-life balance, compared to a global average of 60%; a similar share are happy with their work hours and, on average, work 39.2 hours per week, compared with 42.5 hours for the global average.

Here are the top 10 countries where expats are happiest with their work lives abroad:

1. Denmark
2. Saudi Arabia
3. Belgium
4. Netherlands
5. Luxembourg
6. United Arab Emirates
7. Australia
8. Mexico
9. Indonesia
10. Austria

Ilana Buhl, a CNBC Make It contributor and American teacher who moved to Denmark, says moving from Texas to Copenhagen brought about lots of positive changes to her work life: shorter workweeks, stronger boundaries around off-hours, five weeks of paid vacation, and a better salary to cover a lower cost of living.

Outside of work, she also enjoys robust public transit, public health care, affordable day care, and ample maternity leave paid for by her employer and the government.

Many of these factors contribute to the fact that Denmark consistently ranks as one of the happiest countries in the world, according to the annual World Happiness Report.

Coming in at No. 2 is Saudi Arabia, where a majority, 75%, say moving there has improved their career prospects, versus 56% globally. The majority, 63%, of newcomers relocate to Saudi Arabia for work, where they say they’re satisfied with the state of the local economy.

Meanwhile, just 35% of expats around the world say they moved to a foreign country for job-related reasons.

The biggest downside to working in Saudi Arabia may be the long hours — expats working there report logging 47.8 hours a week for a full-time job.

Rounding out the top three is Belgium, where expats are highly satisfied with their job security, the local job market and their own career opportunities.

Expats in Belgium say they enjoy flexibility in the workplace, especially among the 68% who say they can work remotely, and their shorter-than-average full-time workweek of 40.8 hours.

Panama was recognized as the No. 1 best country for expats overall, according to the InterNations survey. The overall ranking accounts for broader life and financial factors, where foreigners say they’re satisfied with the quality of life, ease of settling in, working abroad, personal finance and an “expat essentials” index, which covers housing, administration, language and digital life.

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If a pair of sneakers from your favorite brand was marked down by 20%, you probably wouldn’t hesitate to add them to your cart. But what about that same markdown in the price of that company’s stock?

That’s what potential investors in Nike stock have been asking themselves of late.

Last month, the athletic apparel manufacturer announced worse-than-expected, declining quarterly sales to cap off a rough fiscal year, and the market reacted swiftly. Nike shares plunged by nearly 20% in the day following the earning results, the worst trading day in the company’s history.

All in all, the stock has surrendered more than 31% year to date.

If there was a similar decline in a broad stock market index, such as the S&P 500, just about every financial advisor on Earth would tell you to stick to your plan and keep investing in a broadly diversified portfolio. Because stocks have historically trended upward, downdrafts are largely seen as opportunities to buy into the market when it’s on proverbial sale.

When it comes to individual companies, though, the choice becomes much murkier. After all, a stock could take major losses and then soar to new heights à la Apple. Or you could buy a falling stock that becomes the next Blockbuster.

“Buying because the stock price has gone down without knowing some of the underlying issues or without understanding some of the underlying activities, could be problematic,” says Clark Bellin, president and chief investment officer at Bellwether Wealth.

“Something can be on sale for a reason.”

Remember, you should never be making wholesale changes to your portfolio to try to capitalize on any one investment. But if you have a well-diversified portfolio with a sleeve of individual equities, a stock that has fallen precipitously may be an attractive add. You’ll just have to figure some things out before you buy, says Sam Stovall, chief investment strategist at CFRA.

“Any time you have a big selloff in a stock, the question is, will there be more declines in the near future, or is it an overreaction that represents a very attractive buying opportunity?”

Investment pros recommend these three steps to help sort things out.

1. Have a process in place

There thousands of stocks to choose from, and investigating ones that make financial headlines isn’t a great way to narrow things down, says Bellin. “The tendency for a lot of people is to see the dip, then try to do the research to see if it’s something they want to add,” he says. “That’s sort of doing it backwards – and that’s going to cause some problems.”

Rather than scrambling to do research, he says, keep a watchlist of stocks you’d be interested in buying at the right price. That way, you have already done your homework by the time the price slips. You merely need to make sure your thesis on the stock is still intact before pulling the trigger. “If some thing on your target list goes on sale, yeah, go ahead and add a little more to your position,” Bellin says. “Just make sure you’re not overweighting your position. You want to have a fairly well diversified portfolio.”

2. Check the numbers

A stock can hit the skids for a variety of reasons. Maybe the company fired its CEO. Maybe it sunk money into a new product line that the public didn’t like. Maybe investors have soured on a whole sector, and a company has been dragged down alongside its peers.

No matter the reason, it’s important to dig into the company’s underlying fundamentals to see if it’s a stock you want to hold over the long term, says Charles Rotblut, vice president of the American Association of Individual Investors.

“Look at what’s been happening. Look at gross margins and operating cash flows over a period of time,” he says. “See what direction things are headed in. Is this truly a one-time blip? Or has it been a gradual worsening that now appears to be accelerating?”

If the company has major earnings problems, it may be wise to take a wait-and-see approach, says Stovall. “It’s not something that tends to go away very quickly,” he says. “A company has to respond to the issues there, but a lot of times, they won’t do enough the first time around. Sometimes it will take two or three attempts until the issue is fully resolved.”

3. Reassess your outlook

Beyond the numbers, you’ll have to decide if whatever short-term problems that have dragged a stock down represent a meaningful long-term threat to the company’s business.

Ask yourself if investors are overreacting to a problem that’s fixable. It’s not an uncommon occurrence, says Raife Giovinazzo, a portfolio manager at Fuller & Thaler Asset Management, a mutual fund firm that focuses on financial psychology.

“People overreact, in general, to vivid, emotional stories,” he says. “And there’s nothing quite so vivid and emotional as losing money.”

One way to tell if the public is overreacting negatively on a stock is to see if higher-ups at the company are buying – a move that must be publicly disclosed and is available on free sites such as Nasdaq and Yahoo Finance.

“The number one thing we start with is insider buying or share buybacks,” Giovinazzo says. “That’s the event that says, hey, management is not just saying that they think that there’s an overreaction — they’re actually doing something about it. They’re putting their money where their mouth is.”

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