[tidenly]

One common issue I see with programmers is that they often think a knowledge of technology alone is enough to identify and fix problems in a field.

You actually need a domain expert, or to become one yourself, within some field to even begin to know what the current issues faced are, what technologies or products are already in use, and what kind of solution would be acceptable in the market. The balance then of finding the solution is actually much more 50/50 than a lot of tech people want to believe - its not just them sailing down on a cloud and delivering some perfect pre-made solution.

Usually I find these people through my friends or family. You basically have to sit down and interview them, and have a back and forth to find what kind of things would or wouldn't work in their industries. I don't think theres some magic bullet to finding all untapped markets.