The customer in-hand
At USC, where I am a graduate student, the entrepreneurship professors repeatedly stress the importance of “customer in-hand” before starting a new venture. In fact, one of the core courses requires the student to talk to 50 or more potential customers to force you to find out if the perceived demand is real. The reasoning is, if you can’t find a customer who is willing to buy your product today (disregard that the product may be imaginary at this point), then you most likely are fooling yourself. This blog article from the gobignetwork.com reinforces this concept. Its great advice, and will help avoid unnecessary costs and frustration by determining in advance if your product or service actually has a market.