In bowhunting the mountains sometimes one chance is all you get at a big bull. I have a pretty basic regiment for staying focused...the key -- repetition and commitment. It's been fairly well documented that I shoot everyday, at least one arrow. Most days I shoot 20-50, sometime many more. I don't really care about the distance, I just want to go through the routine of pulling back, picking a spot and squeezing the trigger. I shoot in my backyard most often, sometimes in the house if it is dark or outside with my wife holding a flashlight on the target. I am very obsessive about "mastering the shot", or attempting to.
Also, I like to seek out high pressure shooting situations, which I believe helps to simulate the emotional bonanza I will face when a big bull is bearing down, screaming bugles at 20 yards. Shooting in front of a big crowd, participating in high stakes 3-D shoots or just shooting with buddies for skins ($1 a target) can all get you out of your comfort zone and better prepare you mentally for crunch time.