Tell yourself that tonight is not Christmas Eve. Do the same things you always do in your bedtime routine: brush your teeth, read a book, chat with your friends, etc.. Say to yourself: "What am I gonna do tomorrow?" -- like it's any normal day: "Oh, hey, tomorrow maybe I will hang out with my 'bud', ______". A technique that, strange as it sounds, works well is to play a quiet game you can play alone (or with another hyper and excited friend or sibling), such as Mad Libs, while in bed. This will help take away your energy and help you fall fast asleep.  Santa came a lot quicker than you thought! Although this may seem counterintuitive, exercise can help to calm you down. A couple hours before you go to bed, see how many push-ups, crunches, or jumping jacks you can do in your room. Exercise only for thirty minutes, though; you don't want to stay up too late. Exercising is a great way to help you feel physically tired so that your body will want to sleep. Better still, it will take your mind off Christmas for a little while. Having a warm bath will relax your muscles and make it easier to fall asleep. Squirt bath toys at imaginary targets, submerge yourself in bubbles, and relax your muscles. Try scented bubbles and soap. This might spoil any surprises and will keep you very excited and awake! Remember, Santa Claus knows when you are sleeping and when you are awake. He won't come if you are peeking. In addition to providing you with nutrients like calcium, magnesium, and L-tryptophan, warm milk can be a soothing, comforting drink that lulls you to sleep. You can also try hot herbal tea; it is very soothing and calming to drink. Just make sure it doesn’t contain caffeine!  When you're setting up a cookie plate for Santa is a great time to have some warm milk. Or, drink hot chocolate after you are in your pajamas. This will also help you to relax and stay warm! Don't drink coffee. The caffeine in it can keep you awake. If warm milk disgusts you on its own, add some honey. It will make for a relaxing treat. . If you are just jumping up and down and feeling hyperactive, you need to calm down; you're only feeding a buildup of excitement that it'll be hard to come down from. Read a book. Listen to music. Whatever makes you calm down and relax.  Read a book. It can be about Christmas, although it doesn't really matter. Try reading a school textbook, a really boring one from your least favorite class. Read a boring book to induce sleepiness; read an exciting one to get lost in and to help take away the urgency of thinking about Christmas things.  Some good non-Christmas books are Harry Potter, Twilight, School of Fear, and Diary of a Wimpy Kid. They are fairly long and can keep you occupied for a while. Burn a sweet scented candle for a little while in a safe place in your room.  The scent will help you to relax, particularly if you choose a scent like lavender or jasmine.  Just make sure to extinguish it before you fall asleep!

Summary:
Think of it as a normal night. Play a game with someone. Exercise. Take a warm bath. Don't peek at the Christmas tree. Drink warm milk. Relax