Your foundation layer is essential to staying warm and dry. Use wool blend, silk or synthetic technical fabrics that fit close to the body so they effectively wick moisture away from your skin. Cotton is a poor choice because it holds moisture next to your skin.
Rent kid's ski-wear from Mountain Threads where you can build ski or snowboard outfit from the outside in. Select jackets and pants, accessories and base layer, right down to your socks, for a comfortable day on the mountain.