1. Take pictures of your decorations and displays before putting things away so that you remember exactly what goes where when it comes time to decorate again. Jot notes on the backs of the photos if there are specific things you need to remember, and then file them away to use as a reference for next year. You'll be amazed at what a time-saver this is when you are sorting through box after box of decorations after they've been stored away for an entire year!
2. Jot down a list of recipes you made and where they are located while this information is fresh in your mind so you don't have to search high and low for them next year.
For the above two ideas, I actually have found that creating a file specifically for Christmas-related items is really handy. In it, you can place your Christmas card list, gift lists (it is always nice to have these to look at next year to ensure you don't give duplicate gifts!), and any other pertinent information to have at your fingertips the next time you need it.
3. Use tape to label strands of lights outdoors so you know exactly where they go next time (north roof line, south roof line, etc.). Replace any bulbs that are burned out now, while you still remember which ones need attention. Take time as you are packing them away to loop them nicely, and then secure with twist ties. Trust me: you will be thankful next year that you took the time to do all of this when you aren't struggling to untangle endless light strands with too many spent bulbs to count!
4. Take inventory of things you lacked this year, and see if you can hit up some post-holiday sales to pick up those items while they are deeply discounted. Pack them away with the rest of your decorations to be at the ready next year!
5. If you have children, help them clean out their toy box before flooding it with their newer things (and therefore creating lots of clutter!). Have them find a particular number of things they would like to donate to charity. If there aren't any toys they are ready to part with, try boxing up a few things to put away in storage to pull out again later, after the newness of their Christmas gifts has faded. It is amazing how much a month of not seeing a toy can revive a child's interest, and it will help ensure your home isn't overrun by so many gadgets and gizmos!