When you are hunting with a bow or any other difficult to aim weapon, equip yourself with the spotting scope. Zoom in and line its crosshairs up with the deer. Then, switch to your weapon. If the deer has not moved and is in range, your shot should be dead on. You can also aim the scope a slightly over the deer to adjust for the drop in the arrow (or bullet). With some time and practice you will kill them every time with this technique.