For many entrepreneurs, the process of launching a company begins with the lightbulb moment when they conceive of a breakthrough idea for a new product or service. Very often, they are so passionate about the idea that they believe its merits will be self-evident to prospective customers—that the innovation is so obviously superior it will sell itself. Entrepreneurs who avoid that delusion may think of their initial sales as a chicken-and-egg problem: They realize that getting buy-in from potential customers is a top priority, but until they design and build the product (which often requires securing funding, assembling a team, and many other tasks), how could they possibly make a sales call?

A version of this article appeared in the May 2013 issue of Harvard Business Review.