Hanging stands in the fall can be a piece of cake because there are leaves all over the place, and it's easy to hide a stand. All of a sudden it's November and you realize you're sticking out like a sore thumb. I've found that about 18 to 20 feet is a good height. Too much lower, and they seem to spot you a lot easier. At 20 feet or so, they seem to notice you much less, even if you don't have good cover. I don't hunt much higher, it doesn't seem to have a benefit, as far as my experience goes, anyway.
I don't do anything to brush my tree stands in. I just try to position them so as I expect the deer to approach, I'm either in line with the tree, or behind it. But deer never come where you expect them to, so no matter what you do, deer will always approach from the side. The biggest mistake I made when I first started hanging stands was putting them too close to the trail. I like to be about 20 to 25 yards from the trail, and set up so I have a shot as the deer is walking away from me, hopefully with a quartering angle. If you're much closer than 20 yards, they pick you up a lot easier. But if you sit real still, you can have deer right under the stand and still get a shot, so you just gotta do what you can with what you got. I've had deer walk between the tree and the ladder to my ladder stand and still managed to get a shot. However, it's a lot easier on the nerves if you have some space to work.