That's a great question! Writing a Christmas card for your girlfriend can be a great way to express your love and appreciation for her. Here are some ideas to help you get started: 1. Start by expressing your gratitude for having her in your life and how much she means to you. 2. Share a special memory or moment you've shared together and how much it meant to you. 3. Tell her how much you look forward to making more memories with her in the future.