Short and pleasant greetings should appear at the start of your letter as a festive manner to address your card recipients. A simple Christmas greeting may go a long way, and it's the perfect way to start your personalized message. "Merry Christmas!" or "Happy Holidays!" are traditional greetings. If you know the person receiving the card, write a personal message. This will demonstrate to your card recipient how much you care about them this holiday season. Personalize your Christmas card thoughts by including information specific to the individual receiving the message. Make comments about some big news, a special occasion coming up or a new addition to the family to go along with the rest of your greeting.