As a Soldier for 25 years (4 of which was with the 10th Mountain Division - cold weather experts), we would train our Soldiers how to stay warm in all types of cold weather environments. If you'll remember the word COLD, that will help a bunch.
CLEAN. Keep the fabric clean. When the fibers are clean, they breath the way they're designed to work. Clogged fibers keep dirt and moisture next to your skin, making you cold.
Avoid OVERHEATING. Move slow. When you move fast, you sweat. Sweat = wet. When your body temperature drops back down to normal now you're cold AND wet. Not a good solution.
LAYERS. Wear light, loose layers. These layers trap body heat. Particularly for feet, tight = cold!
DRY. When you get wet, dry off. When you get wet from activity, you'll normally sweat on your head, back and feet (short of full body, dripping sweat). Change your t-shirt and socks and wipe the sweat off with the damp t-shirt. If you don't have a dry t-shirt, remove the damp one, let it dry for a while. In the mean time, put your shirt/ sweat shirt back on w/o the t-shirt. Rub your skin/ bare feet in your bare hands to stimulate blood flow and to dry them off.
Lastly, your mentality determines how cold you feel far more than the ambient temperature. Stay positive and focused, determining that "this isn't the coldest I've been. Remember that time when it was so cold? This is NOTHING compared to that!" That may sound silly but it really works!
I hope this helps!
