I mentioned wools socks and mittens because wool tends to be warm even when wet and does not melt or burn as readily as synthetics. Try handling a hot pot of water or stoking a fire with synthetic mittens and you'll be spending a very stressful few seconds shedding liquid polypropylene from your fingers. Also, sleeping with the liners in your sleeping bag or on your feet at night means that you won't be putting your toasty feet into icy cold boots when you wake up. Construction Equipment Don't forget the shovel, and axe. A small Sven saw or bow saw is excellent as well.
Many hardware stores sell a folding travel shovel that can be stowed in a trunk for emergencies.
While most of them are too flimsy to be of any use on a winter camping trip a few models do hold up to the abuse that you can give them. I prefer to buy a non folding polyethylene or aluminum type and simply strap it on the outside of my pack. That way when I arrive at my prospective campsite I can commence the task of constructing a kitchen or shelter immediately without having to route through my pack to find that elusive folding shovel. An axe, while not vital can make clearing debris and securing firewood much more pleasant as will a portable bow saw. Often in the winter wood will appear dry because the moisture on it is frozen but when you put it on a reluctant fire, the moisture puts the fire out.