People have problems, go and meet people. Pick an industry you think you might be interested in exploring and then start attending their meetups and events. Speak to people, ask them what their problems are. A great place to start is finding industries where most people you meet describe themselves as "not technical" or "bad with technology", they're often massively underserved. You'll know you've hit gold when you s…
Point 1 makes things easy, 2 and 3 are harder because you have to create and incentive to onboard people onto your product that doesn't exist yet. So actually there's a point 4. You have to do a market scan, and either become an integration expert at some extendable technology or build something new. And then you're developing goes from developing to selling. And then to support.
It's hard to beat excel.