RE: Need some WISDOM
Okie - Here's how I learn to control my nervousness - I practice a fair amount - maybe once/week over the summer. When you're practicing, you are generally relaxed, which is not an accurate replication of the hunting scenario. You need to do something to make yourself nervous.
I stand on a 5-gallonbucket. Stupid, I know, but when you're standing on that bucket, you're worried about wobbling around, you're worried about tipping over, and your heart starts to race. If that doesn't quite do it, just add some elements of difficulty (angle the target, shoot under a limb, make yourself a narrow shooting lane, etc.). It's not exactly the same type of nervousness that you'll experience in your treestand with that buck approaching, but it helped me.
Just give it a try, and see if it helps.