The Anatomy of a Killer Business Plan | Inc.com
You have to figure out the group of customers that you want to sell to. Then you have to develop an interview guide—a list of questions such as why current products don’t meet their needs, what an ideal product would look like, how they decide among competing vendors, and where they perceive an unmet need.
You should then interview at least 20 potential customers and make sure your analysis of their answers to these questions is in the business plan. And your analysis should include key quotes from those potential customers that reinforce the conclusions.