I practice from a tree, shoot out of the second story windows of my house and play out as many shot scenarios as possible. IMHO you can shoot until the cows come home, but if you aren't mentally prepared you will screw up. When I go to bed at night I imagine myself in my stands and play shots in my head. I see the deer walking along specific paths by my stands and play the scenario out in my head and imagine.
In the last four years I have only missed one shot. That shot was due to a deer jumping the bow and me shooting too high because I misjudged the yardage due to the height of the stand I was hunting and not being prepared. One thing that makes me more successful at bowhunting versus my father is my ability to control my nerves before the shot. My father wil outshoot me any day of the week with a rifle or bow, but for some reason I outshoot him every time there is a deer standing 10-30 yards out.