People often credit their success to confidence and courage. Emma Grede has another word for it: naivete.

"I didn't know anyone growing up who had their own business," Grede tells CNBC Make It. "So I really didn't know what I was getting into."

In 2008, at age 26, Grede founded her own London-based entertainment marketing agency, ITB Worldwide. Over the following decade, she moved to Los Angeles and launched apparel lines with Khloé and Kim Kardashian — denim brand Good American in 2016 and shapewear company SKIMS in 2018, respectively.

Three years ago, she sold ITB Worldwide to PR agency Rogers & Cowan for an undisclosed sum. Today, she's the CEO of Good American and, as of last month, the first-ever Black woman investor on ABC's "Shark Tank."

None of that would be possible without her naivete, she says — if she'd known what she was doing, she might not have worked as hard to assess and address the gaps in her knowledge.

In other words, Grede says, that's the key to her success: Figure out what you don't know, and then make a plan to learn it. Here's how she does that.

How Grede analyzes her weaknesses — and works to strengthen them

As a teenager, Grede matriculated at the London College of Fashion, and quickly realized she knew little about how the industry actually operated. So she chose to study business, focusing on behind-the-scenes areas like planning, merchandising and partnerships.

At age 19 — a typical graduation age in the U.K. — she secured a job in sponsorships with a fashion show production company. Sitting in on deal meetings and talking with designers, she found out just how much work goes into building client relationships, so she made it a point to study and learn.

She decided to take those lessons and launch her own marketing agency seven years later. "I had been around a lot of people, seeing clients and deals," Grede says. "I just imagined, 'Well, if they can do it, why can't I?'"

It was a sizable jump. Her husband Jens, a Swedish fashion executive, helped fund the start-up in its early days through his own fashion company, Saturday Group. But Grede still says her first six months were the hardest, spending hours on the phone, cold calling clients, and taking only a "menial salary" for herself.

"On separate occasions, [I] hired people that I was paying more than myself," she says. "I knew that I needed to compensate for my own inadequacies or gaps in my knowledge."

Grede says those phone calls taught her how to listen: She'd hear prospective clients describe what they wanted, and then speak their own words back to them. "I can't tell you how many pitches I have won in my life [that way]," she says. "They'd say, 'You understand exactly what we need.'"

That, she says, is how she landed major brand partners, like Dior — opening the door to celebrity clients like Natalie Portman and Kris Jenner, and eventually leading to her partnerships with the Kardashian sisters.

In hindsight, she says, launching a start-up at age 26 or uprooting her life in England to move to Los Angeles might not have been the smartest ideas at the time. But that doesn't mean she regrets them now.

"I actually look for those opportunities in my life, where can I learn or put myself into situations where I'm a little bit unfamiliar," says Grede. "Because actually, I think that is what helps me to grow."

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