I always think about who's in control.Am I controling the shot or is the bow controling the shot.Rigidly sticking to a shot sequence is key,as said previously if any element of the shot sequence unravels you let down and start over.Blind bale shooting as Rob was talking about is a way to burn how shooting in a relaxed way should feel into your subconscious mind.Close to the target,your eyes closed,just feel the shot,completely relaxed.
Shooting to quickly is a form of Target Panic.Relax and take your time,and if any thing doesn't feel right let down.Simple but not easy.
I struggled with a bad case of target panic years ago.I have a couple of books and a tape series that deal with conquering it.If you think they would be helpful you are welcome to borrow them.