Another approach, if you want to create something for a lucrative market but you're not a user, is to co-create your product with customers. This piece on how to identify a monetizable pain is great:

http://www.forbes.com/sites/nathanfurr/2011/11/18/nailing-th...

Clay Collins also advocates for a similar approach that he calls the "interactive offer":

http://mixergy.com/collins-interactive-offer-interview/