Diana Kander has an interesting view about that in her book "All in startup". She mentions that it is not enough to find a "headache" the people have (problems they can live with), you have to find a "migraine problem" (problem they'll do anything to get rid of).
Obviously, you still need to get the people to know about your product.
This is necessary but unfortunately not sufficient. You still have to do all the sales and marketing grunt work. It is amazingly hard to get people to pay money even if they love your product. Brutal and depressing.