Food and drink
Start by making your list and checking it twice. When you're buying food for Christmas, try not to buy too much, and think about leaving things like disposable plates, cutlery and napkins off the list.
Take your re-usable shopping bags with you. You can leave them in the car so you'll always have them on hand when needed.
Why not cut down on your beer miles and drink a local brew or try a local winery? You could even choose from the increasing range of organic or carbon neutral beers and wines.