Ultimately we're good learners. Once you get beyond things like breathing, and startle reflexes, that you can't stop even if you want to, very little that we do is truly instinctive. However, we do learn to do a lot of things, generally by repeating them until we're consistently successful without consciously thinking about them. When you get to archery, we tend to call that learned behavior instinctive shooting because it no longer requires conscious analysis.
McDave's first post on the subject is right on.
If we had historically relied only on our instincts, we'd have been extinct long ago. We're slow and have no natural weapons - no claws, teeth too short, etc., so our ancestors would all have been eaten eons ago.