Two things come quickly to mind... well, maybe three.

One, you can never hurt yourself by improving your yardage-estimation skills.

Two, take those skills and just estimate the yardage to the object you want to shoot -- but at the height you're at. There's usually a tree (in my case anyway) close enough so that you can look at it on a level playing field, if you will.

And three... when I'm in a treestand, I usually range a few key landmarks (twisted trees, etc.) from my stand before the hunt really begins so that I'm ready when the deer does walk by. That's been my most effective utilization and most oft-used method for my rangefinder. Of coursse, if you don't have one... keep working on your yardage-estimation skills!