It's pretty easy if you search out your faculty members. At least it was for me. Most of them are looking for some wide-eyed student who doesn't mind doing the grunt-work. I hooked up with an Endo professor who already had a project mapped out. All I had to do was the work. Many times it is lit searches and stuff you can do on your own time, not things you have to commit every Tuesday afternoon (or whenever). I did a lot of work when classes and clinic were slow, and I slowed down when exams rolled around. The have all been through it and seem to understand. Just talk with them. If nothing else, you will demonstrate that you are eager, a hard worker, and willing to go the extra mile. These qualities are way more important (in my humble opinion) than how much you publish.