I cover switchbacks to a certain degree on my bike tips page. (see my sig)

I think the hardest thing is just committing to the turn. If I think it looks too hard, I'll just bail, which becomes a self fulfilling prophecy at times.

There is a trail around here with 50+ switch backs... most of them are really nice rounded ones. Some of them are tight and a few of them are a bit technical so you have to power up them.

I find really technical ones... rock, boulder and roots combined with a turn to be the hardest. That and the V=shaped ones.

irulan