Dress in layers of either wool or fleece. Cotton is a big no no if you want to stay warm. Wool is the best because it will still insulate even if it is wet.

My insulated underware are made of polly propelene, the same stuff that is issued to the military. Works great.

Do not wear boots that are too tight as this will cut off some circulation to your feet. Your socks should start with a persperation wicking liner then one or two pair of wool socks. Merino wool is the most comfortable, non itching wool that I have found.

Wear an insulating hat. You loose the majority of body heat through your head and ears. Another place that you can potentially loose a lot of body heat is your groin area.

Mittens will keep your hands much warmer than gloves ever dreamed of. There are many mittens out there that allow you to use your fingers through a slit in the palm of the mitten. I won' t wear anything else. A wool glove style liner inside the mitten is a great addition. It also helps when you have to poke out your fingers and touch that cold bow or gun.

Biggest thing is to keep your torso as warm as possible. Your body will begin restricting blood flow to your extremites if your core is getting too cold. That' s why your feet and hands get cold first. So do not over exert yourself getting to your stand. If you sweat you will get cold once you stop moving.