What's your process for finding out if an idea has potential?

Hey folks, I read 'Make' by Peter Levels years ago and found his process quite interesting:

1. Spending a week listing your personal problems,

2. Rank them, then look for solutions for the top three.

3. If nothing meets your needs, build it.

The beauty of this is that simply by doing the exercise, you end up meeting some of your needs by discovering something out there.

What I’m missing now is how to identify a market signal after your MVP, or even before, to know if it’s worth continuing to develop.

Do you have any thoughts or book recommendations?