I could never draw too soon either. For me, It was either right before the shot or not at all. I used to stay on my feet for the first 90 minutes or last 90 minutes of the day to eliminate the chance of spooking deer when trying stand up. Then, I learned to stand as soon as I saw deer approaching (if possible). Lately, I have had deer all up under me and couldn't get a shot off with a crossbow because they were too much under the stand. It is far better to let them walk than risk taking a bad shot.
In the past few weeks, I have had a few deer look up at me that kept trying to do that head bob thing to fake me into moving. I have too much practice to fall for that kind of thing, but you still have to sit motionless for however long they want to play that game or risk freaking them out. I'm seeing plenty of deer, I just haven't seen the right buck yet. I love this time of year.