There are a million things that can ease a track job before the 1st drop of blood is even searched for. When you shoot the animal watch it HARD. Notice everything you can about the way it ran, the direction it ran and MARK THE LAST PLACE YOU SAW IT. When you get out of the tree you'll have no clue where it went without a firm landmark./compass reading what ever it takes. Also as much as I stress watching and soaking in everything you can, don't believe everything you see either. Angles and low lightcan wreak havoc with where you think you hit a deer. Try to see as much and as accurately as you can, but allow for the possibility that you may be wrong. One last tip is only follow what the sign is telling you. Don't skip ahead, don't "think" where he went, just follow the sign. THEN and ONLY then if all the sign runs out, start thinking and guessing and don't always pick the obvious. If there is one rule about trailing a wounded deer is that there are no rules. And also, foolow blood trails for practice even when you see the deer go down.