Zak pace off some know distances and mark them with flagging tape or some thing you can see from your stand. Do this in a circle around your tree in 4 locations and you will know that the deer is in your kill zone. It will give you a reference point that you can go by for longer shots. Take mental notes of tree's and brush while your in your stand and guess at the yardage and pace it off after your hunt this will help also. Hope this helps and good luck.