Nearly everyone can make money with Amazon, Facebook, and Etsy side hustles that generate $125,000 or more annually.

Sarah and Jamie McCauley are multifaceted entrepreneurs, with a variety of income streams that include being landlords, YouTubers, Walmart pallet flippers, eBay resellers, and Amazon product reviewers.

The McCauleys generate their income by researching profitable side hustles, testing them, and teaching others how to do the same on YouTube. Last year, the Grand Rapids, Michigan-based couple earned nearly $140,000 from eight streams of income, as per CNBC Make It's review of their financial documents.

Their YouTube channel, which has over 146,000 subscribers, is particularly successful in two areas: real estate and showcasing their side hustle endeavors.

According to Jamie, it is feasible for almost everyone to earn extra money on the side to pay off a credit card debt or go on a vacation.

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A growing number of Americans, including the McCauleys, are part of the side hustle revolution, with about 39% of U.S adults having side hustles today, driven by necessity, precaution, or a desire to increase their earning power.

Building a profitable side hustle is becoming increasingly challenging due to the growing competition, despite the ease of starting with platforms like Amazon, Airbnb, and Fiverr providing instant access to paying customers.

I interviewed several Americans who have successful side hustles to understand how they built their businesses and used them to achieve various financial goals. Each respondent emphasized four key traits that contributed to their success.

They tailor their product to their audience

To be successful in selling anything, you need customers who are willing to purchase it. Jenny Woo attributes her side hustle's success to her extensive research on her target audience and customizing her products to meet their specific needs.

At the University of California, Irvine, Woo is an adjunct lecturer and a freelance business consultant. She teaches an online course on emotional intelligence and runs her own business, Mind Brain Emotion, which sells 12 different card games related to emotional intelligence.

Last year, $1.71 million was earned on Amazon, as per reviewed documents by Make It.

Woo's first deck of cards, "52 Essential Conversations," aimed to help parents connect with their kids and improve their emotional intelligence. She researched by joining parenting Facebook groups and analyzing users' posting, commenting, and liking behavior.

Woo continued researching after selling $10,000 worth of the game in a 2018 Kickstarter campaign. She discovered that "overwhelmed" teachers looking to support children's social and emotional development made up a significant portion of her audience.

Her second deck, "52 Essential Relationship Skills," was designed for teachers but did not sell as well as her first deck. However, it taught Woo that she could expand and merge her audience.

"52 Coping Skills" was the third game that Woo applied the lesson she learned to, using her own experiences with college students during the Covid-19 pandemic and her ongoing research on teachers and parents as inspiration.

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

They find a platform suited for their product

Woo targets broad audiences on Amazon, while Tim Riegel focuses on a more specific customer base on Etsy.

In Lamar, Missouri, a full-time general manager at a sheltered workshop named Mozark Fire Pits creates firepits using recycled tank ends. These firepits weigh an average of 225 pounds and are sold for $950.

Last year, Mozark Fire Pits generated approximately $202,000 in revenue on Etsy, according to reviewed documents. Riegel claims a 40% profit margin.

Etsy was chosen by Riegel over Amazon, Wayfair, and Overstock because it felt more user-friendly and suited his personalized products. Although he also sells on Facebook Marketplace, which has higher advertising costs, it offers lower shipping costs for customers within a 200-mile radius.

No matter the type of side hustle you run, conducting a platform analysis can be valuable.

If you offer a service instead of a product, you may want to explore platforms such as Fiverr and Upwork, which are popular among photo editors, marketing writers, and voiceover artists. Additionally, Taskrabbit is a well-known platform for labor-intensive side hustles like cleaning or repair work.

If your gig is popular among many people, consider joining niche marketplaces like Contently, Skyword, or ServiceScape, advises side hustle expert Kathy Kristof.

A common issue with many freelancers, according to Kristof, who runs the blog SideHusl and has reviewed over 500 side gigs, is that they frequently use well-known online platforms that are highly saturated with long-term users.

They stand out on saturated platforms

To stand out on any platform, you need a listing that is clear, concise, targeted, error-free, visually appealing, and optimized for search engines.

Becky Powell, a kindergarten teacher from Beaverton, Oregon, earns extra money by selling worksheets for other educators on Teachers Pay Teachers. Her worksheets often center on her area of expertise, teaching children how to read by sight.

Her side hustle didn't gain momentum until she adopted SEO strategies. Upon posting her initial worksheets, she labeled them, "Developing sight words with pattern blocks." Sales gradually increased.

Powell says that her bestselling products were the sight-reading worksheets, which were suggested by her husband Jerome, who has a business background, and had a simpler title, "Hands-on sight words."

Powell's store generated $125,500 in revenue in 2022, as per documents reviewed by Make It. Additionally, her husband sells worksheets on the platform, and they have used their combined earnings to fund vacations, pay off their mortgage and student loans, Powell states.

"To succeed in business, you must possess passion, knowledge, and a business sense, including understanding SEO."

To increase your visibility on platforms, focus on earning positive reviews from customers by providing excellent customer service, prompt shipping, and quality control, advises Kristof.

They know when to change direction or walk away

Sarah explains that the McCauleys have a rule for their ever-changing collection of side hustles: "To be successful, you either have to be one of the first to get there or your approach has to be very unique and different."

In 2020, the couple was among the first to embrace the trend of pallet flipping as a side hustle. They purchased pallets of returned goods from Amazon, Walmart, or Target at local warehouses, unpacked the items, and resold them for a potential profit.

The McCauleys made an estimated $19,500 in profits from pallet flipping from December 2020 to December 2022. Their most popular unboxing YouTube video received 5.4 million viewers, resulting in an additional $30,000 in advertising revenue, according to Jamie.

In 2020, the popularity of pallet flipping among Americans increased. However, the rise in pallet prices and the decline in resale values led to a decrease in the McCauleys' viewership. According to Sarah, "The pallets were no longer worth our time in terms of time versus money."

The McCauleys would have shifted to a new side hustle four years ago. However, they now feel the pressure of constantly creating new gigs and are restructuring their income streams into fewer, long-term projects.

Instead of flipping their current home renovation project in Northern Michigan for a profit, they plan to keep it as their own vacation house and part-time Airbnb rental.

"We knew that side hustling would eventually come to an end," says Jamie. "It's a game for the young to always be searching for the next opportunity."

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