Don't let other people's judgments drain your faith in yourself, especially when it comes to pursuing big ideas.

That's advice from Gregg Renfrew, who knows something about becoming successful by sticking to her convictions: Her clean beauty startup Beautycounter was most recently valued at $1 billion, as of April 2021.

Beautycounter came a long way in a decade's time. After founding it in 2011, Renfrew picked fights with a massive beauty industry led by much larger competitors, lobbying for tighter regulation and calling out potentially harmful chemicals used by many of her rivals. "Everyone thought I was crazy," Renfrew, the company's CEO, tells CNBC Make It.

Instead, Beautycounter gained enough attention and sales to help the business grow into a billion-dollar brand. "People so often don't move ahead with bold and courageous plans and ideas because they allow others to tell them that it's not possible," says Renfrew. "I'm here to tell you it is possible."

Everyone experiences self-doubt and criticism. In some ways, humans are wired to be naysayers as a way of avoiding unnecessary risks, research shows. But ultimately, you need to build your confidence to be successful, Renfrew says.

Self-confidence can help give you the push to take the sort of calculated risks associated with bold ideas, like launching a new business or attempting a big career move. Trust your instinct enough to know when it's time to jump in with both feet, says Renfrew.

"You genuinely have everything you need to be successful, and don't let anyone tell you otherwise," she says. "Don't allow for other people's points of view [to cause] you to doubt yourself."

Take big leaps — just not blind ones

Renfrew started her first business as a college student, building a team of employees to clean homes in Nantucket, Massachusetts, during the summer. In her 20s, she turned a side business selling bridesmaid dresses into The Wedding List, an online bridal registry startup that sold to Martha Stewart Living Omnimedia in 2001.

One key lesson from her career, she says: It's useful to pay attention to what's going on in the world, because global trends can help you spot potentially overlooked opportunities. Use that information to make strategic decisions about every potential opportunity you might take.

In Renfrew's case, watching the 2006 documentary "An Inconvenient Truth" sparked her own interest in the environmental health movement, she says. The film's popularity led her to believe consumers would appreciate products that eschewed potentially harmful chemicals, so she made that a central tenet of Beautycounter's strategy.

If you aren't sure whether a decision is worth making, you might not have enough information yet, says Renfrew. "[Most] successful businesses have founders and/or executive leadership that is paying attention to what's happening out in the world at large and the zeitgeist, or what's happening in culture," she adds.

Renfrew isn't the only person to endorse thoroughly researching any opportunity in front of you. CEOs like Rocket Lab's Peter Beck and Ellevest's Sallie Krawcheck have told Make It that their success hinged on their ability to balance methodical research with the willingness to take smart, intentional risks.

"Knowing when to strike — it's an art and a science," says Renfrew. "There's data, and then there's also just your gut instinct."

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