Socks: Wool is always a great idea.
Walking Shoes: Again Lightweight, comfortable and water resistant. Always make sure you break them in before your trip.
Rain Gear: A good quality rain suit (both top and bottom) is important to keep you warm and dry.
Warm Jacket with Hood: A great idea is a jacket with a water resistant shell and a fleece liner.
Day Pack: A small pack with shoulder straps that you carry on your back. Large enough to hold rain gear, an extra sweater or warm vest, lunch, water bottle, binoculars and other essentials.