Personally, I think the excitement or rush of "buck fever" is part of why we hunt. It's exciting and enjoyable. Breathing helps and so does range time (under stress, we tend to revert to what training we've done or panic if we haven't trained). Thinking your way through the shot also helps. If you can get into that zone where you have terrific concentration, things slow down and you control your breathing, body and trigger finger, it's almost a given.
