Aim for where you want the arrow to hit. I once had a D L that was to long and I had to site in from the tree. If your bow fits and you come to full draw it won,t make any differents. Its the same for for me, ground or up the tree. Think about where your arrow will exit. Don,t get to technical. Just get out there and practice. You will become better at judging ranch and knowing what your bow and arrows will do the more you shoot. If you feel you need a range finder, used one,but todays bow are very flat shooting out to normal ranges you would take a deer at.