Tape foot areas prone to blisters prior to start of trip. Get this info. Wear synthetic fabrics such as polypropylene, Coolmax, polar fleece, nylon, etc. Dress so that base layer doesn't have to be removed. T-shirt or long sleeve shirt, tights or long john bottoms, socks.
Wind pants help if it's really windy.
You build up heat while hiking, especially uphill, and quickly lose it when you stop, or when you reach a ridge line and are exposed to the wind. Pack sleeping bag and clothes in water proof stuff sacks. Especially have a water proof stuff sack for your tent because a wet tent inside your pack will get other gear wet. The best way to pack depends on whether you're using an external or internal frame pack. In general, your sleeping bag should go in the bottom of your pack or at the bottom of the frame if using an external pack.