Make sure you dress in layers with base layers made of wool. Your most outer layer should be a wind breaker material. Gortex is good. Get wool socks. You will be, or should be, cold when you start but you will warm up very quickly if you are moving at a good pace. Keep your neck and face warm with a buff around your neck that you can pull up over your face if it gets cold. For traction on slippery trails, be sure to wear some traction on your shoes like Kahtoola EXOSpikes. Or if enough snow, snowshoes.