Q: What if you are offering a service, such as carpentry work, and you know there is a market. How can you go about testing whether your business will succeed?
A: I know someone who started a home interior design company. He knew that people would spend money on home refurnishing, but would they want to buy it from him? He spoke to prospective customers, to find out why it was that they wanted to remodel. It turned out that many potential customers in the place where he was based were women. He had the realization that they were not just buying home remodeling, but the sense of control a designer could create for them over their environments. He tried out tag lines for his business until he found a hit—which enabled him to market himself as offering something they could not get elsewhere. The tag line he chose was “unlike your husband, we listen.”
Link to that Smart Money article, "Older Americans fuel entrepreneurial boom."