You dont need to go and hanga stand in your yard to practice treestand shots. I assume you have a roof... use it. Or a balcony if you live in an apartment complex. Granted if your on the 5th story, this advice isnt valid [8D]

The one thing to remember, when judging yardage, is when your 25 feet up in a tree, look straight ahead of you and find something close to where the deer is standing. Looking down at the angle WILL throw off your judgement if all you practice judging is on level ground. Look for a tree or other object thats in line with your line of vision at 25'. Makes judging yardage much easier for me!