Well I don't know about getting completely undressed like Kaiser suggests, but if that works for you Kaiser, more power to you.
As a skinny Canadian lad, with little fat to keep me warm, I have tried a variety of things to keep me warm in the stand. As long as you wak into your spot with minimal clothing on, you should be ok. Make sure your under layer does not hold moisture well (cotton bad, wool good), and let your under layers dry a bit before puttin your outer layers on. It is also important to have a good outer layer that breaks the wind.
It's very important to not sit directly on the ground, but have some sort of insulating seat. I have one that clips to my belt for when I am walking/stalking.
Also focus on a couple areas where you can loose alot of heat. My hat is ugly as sin, but keeps me warm. I don't like covering my ears, but when it's really cold, I'd rather have those ear flaps down and be warm and alert than be cold and miserable. Alot of heat can also be lost at the back of your neck. I like to bring a snug neck warmer (we call them dickies here) that pulls over my head, so I can put it on and take it off easily.
I find electric socks irritating because of the heavy batteries, but heat pads slipped into pockets are a great idea.
One last thing, eat some high carb foods before you hunt to give your body the energy it needs to keep you warm. Bacon and egg bagels are a good start to the day.
Cheers,
Tenpoint