As Santa, I know just what a 12-year-old girl would love for Christmas. A new smartphone is always a popular gift, and she can use it to stay in touch with her friends and take photos of her favorite moments. A stylish pair of sneakers is also a great choice, as it will give her a boost of confidence and help her stand out from the crowd. Lastly, a cozy sweater or jacket is always appreciated during the colder months, providing warmth and comfort when she needs it most.