I've always had a problem keeping warm enough to stay in a deer stand all day in our cold Wisconsin winters. Once the cold chill hits, it's hard to stay still. Neck Gaiters are a great way to cut down on that chill. I have seen alot that don't cover well enough and some are expensive. If you have an old pair of long underwear, sweatpants, or even loung pants that are worn out, they may not be ready for the trash just yet. Here's what I do.
Cut the leg from the top of the thigh down to the knee area. Base the length on your head and neck size. You have to be able to put it on and still breathe! Try it on before the next step and make sure it's comfortable. Ok, next lay it flat, and cut slits on both sides up to 8 - 10 inches from the knee (top). This will create two flaps, front and back. So when you put it on there is a flap over your chest and one over your back. It may not be the most fashionable thing, but it will keep you out there longer!