[d0m]

One great way is to focus on personal problems (instead of "ideas"). Solve it in a very hacky way for yourself and then share it with people, see if it helps others. If it doesn't, no big deal, you've solved an annoying problem for yourself without investing too much time. If others like it, then you can see if you want to take it to the next level. Most first-time founders started that way.

Interesting essay on this subject: http://www.paulgraham.com/startupideas.html