If you have a day job, look for the problems that your day job has to solve. Undoubtedly, these problems will be echoed at other companies like yours (and maybe even not like yours), and you have an opportunity there. You might have even been able to work on solving the problem, so you already have a leg up when you generalize it for others by knowing what to expect.

I'm practicing this at the company I work for, and I have many ideas. Be cautious about legality, here, and don't get too specific with how your employer solved the problem, just use the tactic to identify the problems.