There's an Alan Kay video out there, titled something like "How to Invent the Future" (or something close to that). It's in two parts, and it should be available on Youtube. In that video there's a part where he talks about good ways to come up with an idea for a new business. I'd try to describe the process to you, but I really can't do it justice. I'd say go find the videos and watch them and consider giving his approach a shot.
You'll know you're at the bit I'm talking about when he starts talking about the book Human Universals.
You'll know you're at the bit I'm talking about when he starts talking about the book Human Universals.