I agree with the posts above, but would add RUN! Seriously, as long as you have any stamina at all, you can out run a troll. If it's a troll raid, lure them away from your base and run. Keeping some boar jerky on you at all times helps if you need a quick snack.

Another suggestion, if you're in/near a black forest is mark a nearby burial chamber and run to it. The entrance is cover enough, and you can dive inside if you want complete protection.