When I hunt from tree stands, I go a max of about 12-14 feet and hunt in as much cover as possible. You want the deer (I think we're talking whitetails)in as close as you can get them, but you don't want an extreme angle to shoot them at.

Believe it or not, I have most of my stands up ready for this coming season with shooting lanes alreadycutout. Their locations are based on past experience. If I see something is not using the desired run, I would then move to a ground blind (homemade).