1)Obviously, scout your proposed hunting area to insure deer are in the area your going to hunt.
2)Learn your hardwood (nut) trees and know what the deer are eating on in your area.
3)It's very easy to get all excited when you shoot at your first deer. You need to remember where you shot from, where the deer was standing, which way it ran and the last point you saw it as it ran out of sight.
4) Unless you drop a deer right in its tracks with a sure killing shot, do not start trailing your deer to early. If I know I made a good shot with a shotgun/bp(not allowed rifle in Ohio) and deer runs out of sight, I usually wait 45mins. to an hour before I start tracking. If I'm not sure of shot, I'll wait as much as two hrs. before trailing and if it happens to be in the evening, I'll wait till morning before trailing.
5) Carry something to mark your blood trail with. I carry toilet paper(TP deteriorates) and tear small pieces to mark each drop. If you make a high shot, your deer may just spot blood for a good distance. Looking back at the string of TP gives you a general idea of the direction the deer is heading in case you loose the trail.
6) Walk beside your blood trail while marking it. Not on the trail.