Staying on stand and alert is difficult when you're cold. Cold hunters walking to their trucks often get deer moving and push them to hunters who are able to stick it out.
Most hunters know to dress in layers, but there are other things to keep in mind. First, avoid cotton. Cotton holds moisture, which will chill you to the bone. Wear a wool blend or something synthetic like polypropylene for your underwear. The same goes for socks: no cotton.
Speaking of your feet, sometimes less is more. Too many pairs of socks will decrease your circulation, making your toes feel cold quickly. Buy a good pair of boots with the proper amount of insulation and wear one or two pairs of good wool socks. A little room for air to circulate around your toes is a good thing. If you have the room, place a small disposable handwarmer under your toes after you get to your stand.
Next, keep your head warm. A large disposable handwarmer on the back of your neck will do wonders. For complete comfort, a scarf or face mask that serves to warm the air before you breathe it in is the way to go.