pick a stand with a good comfortable seat hight...feet flat, make sure your legs are arent langing down. Warm boots. keep drafts from blowing up your back. Pocket warmers inside your coat, boots and pockets. A big platform that you can stand up on to stretch. a comfortable insulated seat, wider than your but. A seat back to lean against- not the trunk. A neck warmer or balaclava. A widemouth pee bottle.
Ultimate: an enclosed elevated box blind, that allows more movement, keeps you out of the wind, and dry.