I do not believe there is a way, because there is no single answer. Indeed, the number of good answers is unlimited.

You have to look for unrecognized unsolved problems. It's the "unrecognized" that is the bitch in this problem. "Unrecognized" might just be the core feature of entrepreneurship. You have to work hard to uncover it. No easy answers.

I suppose there are established techniques in market research that would help. Ask someone who is good at market research.