Oprah Winfrey, Founder of the Oprah Winfrey Network

Oprah Winfrey didn't grow up with a lot of money. In fact, she had a difficult childhood before her world-renowned talk show, The Oprah Winfrey Show. She ultimately turned her show into a media empire and multimedia production company. Today, she's on a first-name basis with the world as one of the richest and most influential women in the country.

Her best advice: “The truth is, I try not to let other people define for me whether I have power or don’t," she said at an Essence magazine luncheon. "I ended the show, and then there were a whole bunch of people who said, ‘Oh, you don’t have power anymore.’ But the truth is, I know who I am, and the thing about power for me is that it’s connected to a source that’s obviously greater than myself. Any time you can connect to the source and understand that that’s where all of your energy, your creativity, your joy and your triumph come from, I consider that to be authentic power.”