There's a few other things I've started doing, some maybe just luck/coincidence, take all with a grain of salt:
- In a stand bowhunting I MUCH prefer to shoot standing, so I slowly stand as soon as I can, even with the deer way out there.
- Move while they are moving, my theory is when they are moving it's harder to pick up other movement.
- Like Bronco said, if they are looking at you FREEZE, the "head bob" think is them trying to figure you out, depth perception isn't a strength for them and the head movement helps.
- I try to not make eye contact, something about predator/prey relationship. I will usually divert my eyes to the side, or stare at the ground under them, but don't lock eyes. That seems to trigger a run off.
- I've also started not moving after they look away. I swear once they think you are there, they try to trick you, they will start to feed and snap their head up, start to look away and snap the head back, I swear they are trying to trick me. Once they see me, I don't move until they are either walking or I can't see the eyes at all.