Your success as an entrepreneur depends on how well you know your customer. Evan Carmichael shares how trying to sell to everyone leads to failure, while narrowing down to one clear avatar gives you power. He explains why Jeff Bezos kept an empty chair at Amazon meetings as a reminder to always serve the customer. Evan also shares his own story of struggling with a failing software startup, quitting, and then coming back to close a $135,000 partnership by focusing on customer needs.