By Amy Barrett and Amy S. Choi

Getting the Right Idea

You know you want to start a business—but you're not sure exactly what that business should be. Fear not. While some lucky entrepreneurs do get a flash of inspiration that sets them on the path to success, others need to hunt for the right idea. In fact, talk to serial entrepreneurs about how they come up with new business concepts, and you'll find they often have a well-structured methodology for coming up with great ideas. In this slide show, 20 entrepreneurs tell BusinessWeek how they struck gold, whether it was a bolt from the blue or the result of a disciplined search process. (Notes: A handful of the featured entrepreneurs are running early-stage ventures that are not yet generating significant revenue; comments are edited.)