The sense that most people forget about when hunting might be the most important to cover up.
Scent control gets all the glory these days. Whole lines of clothing are dedicated to masking scent. I'm not saying this isn't important; it just seems that people are forgetting about one of the most important things to hide: the noises you make. Hearing could possibly be the strongest sense that deer possess.
An animal's senses are linked to one another. If you don't believe me, think about how you react when you hear something: you turn and look. Deer are no different in their actions. Deer are different in how well they hear.
If you haven't guessed, those ears do more than just outline a buck's antlers: deer rely on them for survival. In fact, a whitetail can even hear at an ultrasonic level. A deer can hear noises you could never hear.
Deer use three primary senses as a defense from predators: sight, smell, and sound. They all work in tandem and connect to others. Sight functions as a scrutinizing sense and a confirmation of danger, or, hopefully in our case, no danger. We all know how to get past a deer's sight; move slow, wear camo, and avoid blue. A deer's eyesight is meant to pick up on movement, but not detail.
So this leads to the other two senses: sound and smell, sound, of course, being our focus. The first thing we need to realize is that as hunters, the noises we make are not natural and travel a long way. Deer actually don't hear that much better than humans do, but they do know what they should hear, and it isn't us. They also have a hearing range that is attuned to sticks breaking, leaves rustling, a climbing tree stand clanging around on my back... Yes, that means a deer can hear you walk in the woods and your boot bang on the stand when you stand up.
So, I know what you're thinking: this has been long and informative, but what does this mean for me?
Well, like I said, these senses work in tandem. In mammals, hearing is just a warning, while sight is the primary sense that is relied on for a confirmation of danger. Simply put, try to limit the noises you make. Move slow and walk in a cadence of two immediate steps and then a pause. If you can, clear a path to your stands free of twigs and dry leaves. Deer have a wide range of vision, which requires less accurate sound information for a deer to nail you. So, if you make a noise, DON'T move: this is when the deer get you.
Above all, for better success, remember that a deer's senses are a system.