Play all the Christmas music one last time as you take down the tree, the lights and the decorations. Eat all the candy canes.
Put back fewer of your “regular” decorations than you took away; make some space for growth. If you like, hit up a thrift store or two - see if you can score a set of throw pillows, laundry baskets or something decorative for your living room. It's nice to have something "new" in the house as you count down to the New Year, and it helps to counteract the blandness of a place newly shorn of its Christmas decor!