From my limited experience in front of an animal, I will say that practicing in diverse situations can be of great help. Things such as shooting with you feet angled up or down such as standing on a hillside will add to practice, as well as shooting from your knees and at in-between yardages. Another idea is that running around before you shoot will simulate that rush of adrenaline. Personally, I tend to blame myself for any type of error in my shot, but making practice more difficult has helped counteract some human errors.