The key to Christmas is to remember what it is supposed to celebrate: the birth of Jesus Christ. If it weren't for Christ, there would be no Christmas.
And the key to keeping Christ at the center of our Christmas is to keep our eyes on Him, and not let ourselves be distracted by everything else that is going on. I know that's easier said than done; Christmas has grown increasingly busy (and secular), and Christ easily gets crowded out by all the activities and the stress on material things.
But as your family celebrates Christmas tomorrow, take time to turn your attention to Christ. Go to church as a family, and take time also to read one of the Bible's accounts of Christ's birth, perhaps around the dinner table. (You can find them in the first two chapters of Matthew, and in the second chapter of Luke.)
Most of all, stop and reflect on why Jesus' birth is so important. Is it simply because He was a great man or was He more than that? The Bible says He was God in human flesh. Think of it: Two thousand years ago, God came down from heaven and became a little baby! "The Word became flesh and made his dwelling among us. We have seen his glory, the glory of the One and Only, who came from the Father, full of grace and truth" (John 1:14). But He didn't stay an infant; He went to the cross so we could become part of His family forever. Have you put your faith in Him?