If you are hunting from a treestand, and you are in a good area, when you see deer, they may be close. Don't get nervous, and only move when you are sure that you can't be seen. Be prepared for a great time, and make sure you observe every safety rule.
Don't take any long shots. I recommend no longer than 40 yard shots, if you are sited in for that yardage, or closer if possible.
Deer can jump your arrow, or scooch below an incoming arrow. Hopefully that won't happen to you, and good luck.]