Before building the multimillion-dollar shoe business TOMS, Blake Mycoskie had already started and sold a handful of companies, including an outdoor advertising company and an online driver's education service. And, as he tells Tim Ferriss in AT&T AUDIENCE Network's new original series, "Fear{less} with Tim Ferriss," the entrepreneur credits much of his success to a simple habit he started at age 15: Journaling. "It goes back to tennis," says Mycoskie, who grew up playing competitive tennis and earned an athletic scholarship to Southern Methodist University. "I wanted to chart my progress. … I wanted to understand if I was really getting better."

Tim Ferriss and Blake Mycoskie AT&T AUDIENCE Network