>>3283407. Practice, practice, practice. You want to make an ethical shot and in the heat of the moment you will be nervous. Developing good form and muscle memory to back up that form will help when you're adrenaline is high because a deer is walking right toward you.
8. Practice in weird situations. If you plan on stand hunting, shoot from an elevated position. If you plan on blind hunting, set up your blind and shoot from there. If you plan on stillhunting, shoot standing, crouching, kneeling, behind objects, etc. You will very rarely be taking a shot standing on level ground at precisely 20 yards from a deer. Also, get a broadhead target and practice with broadheads. They'll fly different than arrows with field tips. Learn with field tips, but eventually transition to broadheads to get a feel for your arrows' performance. Basically, try to replicate the conditions you may find yourself shooting under.
9. Personally, I number all of my arrows. When I practice, I shoot 1-5 so when I get to the target I can see that, yep... #4 was off because I torqued the bow as I suspected. Also, you can identify any that don't quite fly right. When I first tried out a crossbow I was convinced I'd never get the hang of it because I could only nail 2 out of 3 shots. Then I started shooting each bolt several times over. I discovered my #3 bolt was always low and left.
10. Deer will pull a "fakie graze." I had heard of this, so I didn't get busted this time I was stalking close to 3 does, but it was my first time observing it first hand. When they became suspicious that something was up, they walked closer to me where I was crouching (in the open, mind you.. had been moving from bush to bush) to check things out. The lead would dip her head as if to graze, then shoot it back up and look in my direction as if to lull a potential predator into feeling like they could move. Fortunately I didn't budge, but the wind shifted and they scented me. :P