When I"m in my tree, I range tree trunks at eye level with me. Doesn't seem to really make much of a difference though, but it makes me feel better.

NChawkeye makes the key point here, as I've come to realize after 20 years in this game, the toughest shots are often the closest ones. I like to get up around 18-20 feet in my tree if I can, and I really don't like to shoot at a deer inside 10 yards. I try to set up to fling arrows 20-30 yards.That's my killin' range.

At that range, my bow is sighted to drive the broadhead home if I misjudge by a yard or 2, steep angle or not.