Take the time before you decorate for Christmas to attack your clutter. Divide your home into four areas and tackle one area each week before Thanksgiving. Before you clutter your house with Christmas decorations, cards, extra food, etc., clear out unecessary stuff.
As you comb each area, ask yourself if you've used it recently, if it adds value to your life, if it has a home.
One area should include your child's room(s) to make room for Christmas presents.
I found out yesterday that at some Goodwill Stores, you receive a discount coupon if you bring in things to donate! Just be careful not to fill up the areas you decluttered!