Jenny Woo's four streams of income have taught her a few important lessons: how to start side hustles, sustain them and make them more lucrative.

Woo is a 42-year-old ex-corporate consultant and Montessori school administrative director who lectures at the University of California, Irvine, runs an online emotional intelligence course and freelances as a business consultant.

She also has a side hustle called Mind Brain Emotion where creates emotional intelligence-focused card games — 11 of them so far, on topics ranging from relationship skills to job interviews — and sells them on Amazon. The games brought in $1.71 million in revenue last year, or an average of $142,700 per month, according to documents reviewed by CNBC Make It.

The side hustle's success is due, at least partially, to a three-step process Woo followed, she says: Keep testing your idea after you've launched it, use the feedback to inform your next project and repeat the cycle.

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Woo's first game was meant to help teachers and kids learn the basics of emotional intelligence, so she spent three months testing it in local schools before listing it on Amazon, she says. Once sales started coming in, she kept researching and testing the game — but instead of updating it, she used the feedback to create new versions for different topics and audiences.

"Iteration is key," says Woo. "For those who are risk-averse or perfectionistic, they may worry, 'What if I make a mistake? What if I become irrelevant?' Don't be afraid to reinvent yourself."

Preaching reinvention over perfection

Creating iterations of her card game, listing each new version as another product for people to buy, was a familiar pattern for Woo: She has changed careers several times, reinventing herself at each stop along the way.

She helped train managers during stints at Deloitte and Cisco. She worked as a personal trainer. She got involved in school administration when her three children became preschool-aged, and ran a party decoration business called PropMama on the side.

Mind Brain Emotion came along in 2018, as Woo studied for her master's degree in education at Harvard University. She changes things up out of both personal and professional necessity, she says — she gets bored, learns something new, then figures out a way to monetize or share it with others.

"A lot of these [changes] stem from my own pain," she says. "I became a fitness trainer because I was training for a marathon ... My kids needed decorations for their parties, and I wanted to have fun designing them."

Woo isn't the only entrepreneur who preaches reinvention over perfection as a way to develop a business and make more money. Silicon Valley startup accelerator Y Combinator often teaches founders to create "minimum viable products" and release them to the public as quickly as possible, to get real-world feedback from paying consumers, for example.

"Done is better than perfect," Tessa Barton, co-founder and co-CEO of photo editing app Tezza, told Make It in January.

"You learn so much [more] by just getting stuff out," added Barton, whose business brought in $26.5 million in sales last year. "Being on social media, people will just tell you what they like and don't like. Then, you can improve as you go and let go of the fear of launching something."

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