Self-made millionaire Tory Burch shares the best career advice Anna Wintour gave her

Vogue editor Anna Wintour in New York City in January 2017
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Many people know Anna Wintour as the legendary Vogue editor who inspired the tyrannical Miranda Priestly from "The Devil Wears Prada." But to designer and entrepreneur Tory Burch, she's a mentor and close confidant who has helped her achieve success.

Wintour advised Burch through critical points in her career, including launching her first fashion show and approaching investors. She also supported Burch during law-suits with ex-husband Chris Burch.

"Throughout my career Anna Wintour has been a mentor and has given me tremendous advice," Burch tells CNBC. "When I had to face a public lawsuit ... that was not fun. She was a good sounding board and someone who gave me very sound advice."

The best piece of advice Wintour ever gave Burch is one any professional can use.

Editor-in-Chief of American Vogue Anna Wintour and designer Tory Burch attend the Tory Burch Spring 2010 presentation the Salon at Bryant Park on September 16, 2009 in New York, New York.
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"One thing she's always said is, 'Be focused,'" Burch says. "I think that was incredible advice."

"There are going to be a lot of people who weigh in for various reasons and you need to believe in yourself, and your idea," Burch says.

Burch isn't the only high-net-worth individual to say mentorship has been crucial to her career. Bill Gates says Warren Buffett has advised him for more than two decades. Tommy Hilfiger says advice from Leonard Lauder, chairman emeritus of Estee Lauder, was crucial in helping him build his company.

When other people's criticism starts to weigh on your will to push forward, check back in with yourself and refocus on your goal.

Embrace "your unique perspective," Burch says, and be willing to pursue it doggedly. The designer recently launched a campaign called "Embrace Ambition" to encourage entrepreneurs to follow their career goals.

"Be prepared to work extremely hard," Burch says.

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