What’s the difference between a successful entrepreneur and everyone else? People who build an empire from a product or idea are the ones who take themselves off auto-pilot and ask: is there a better way to do this? That one question is how Sara Blakely, the founder of Spanx, went from being a door-to-door fax machine saleswoman in Florida, to the owner of a billion-dollar fashion brand. Here, she shares a mental exercise that helps foster entrepreneurial thinking, and explains why pursuing your idea is so much more important than having people validate it. Basically, here is a lesson in lighting a billion-dollar fire under your ass. Sara Blakely is also the creator of The Belly Art Project, which works with Every Mother Counts to make pregnancy and childbirth safe for women everywhere.