Dress in layers, carry warm insulated coveralls to your stand in a pack, and don't dress warmer than necessary to get to your stand. AVOIDING perspiring is the ticket. A full face warm camo stocking hat is a must. In extreme cold weather I also bring the icebreaker boots(sleeping bags for the feet) and once in the stand I remove my hunting boots and slip on the icebreakers with a foot warmer inserted. Bingo, I never get cold. I also wear an insulated socklike handwarmer(they have a name?) around my waist that allows my thin gloved hands to slip in and out of quietly.