Adding to what PA mentioned...

Ice Breaker has a product called Boot Blankets. They look like huge slippers. You slide you boots into them, and zip up the back. They come in various camo patterns. They are very bulky, but do keep your feet very warm. You can not walk around in them or you will damage the bottom of the boot.

Also from Ice Breaker is their Hand Muff. I have used this product for almost 15 years now. The muff is nicly insulated, and can be worn around the waist so when you need to shoot, it's out of the way. Normally I take a very thin pair of gloves into the woods, just something to wear when ascending or descending a tree with the metal treestand. They also come in a few camo patterns.

I gun hunt in Northern Wisconsin, and it can get cold. These items sure do help when stand hunting.