I also would take a look at how high up you are. I generally set up a minimum of 20 feet up. Wear a harness. Another thing would be if you're just sitting out in the open. If you don't have a good back drop behind you or something in front of you to break up your outline your going to look like a big goofy blob up in the tree. As far as when to draw back, I do like others have suggested and wait until they're behind a tree or looking the other way. I wouldn't wait until they are in the bait unless you don't think you can get a shot until they're there. But if you do have to wait until they're in the bait, just be patient and wait until they're not looking at you to move, as they see movement extremely well.