I seldom read anything that is not of a factual nature because I want to invest my time wisely in the things that will improve my life. Don't misunderstand; there is nothing wrong with reading purely for the joy of it. Novels have their place, but biographies of famous men and women contain information that can change lives.
When you are truly interested in other people, you will learn what they are interested in and if they have a need for your product. If they like you, and most people like folks who take an interest in them, they'll help you find people who do need what you have to sell, even if they don't.