I ended up trying out a completely new niche where there was absolutely no competition and that turned out to be a bust. I didn't actually make a product, but I just wanted to test out the interest. There wasn't any.
Basically, I asked in another thread a while ago about this. I believe the most common advice was to go into a market where I know people are buying.
I've been working with this and I've found a few niches that I've been able to find keywords for and rank well. Plus, I've been able to get some sales with other affiliate products being sold, so I know the people out there are willing to whip out their credit cards.
I know I'm going to have to make a product, plus a sales page and stuff. But am I missing anything? Am I going down the right the path here? Or am I missing something important?