Purchase a large basket. You can find inexpensive baskets at thrift and dollar stores. You could use something the teacher could use in her classroom, such as a large plastic bin.
Start with some practical items. Teachers love to use stickers, glittery markers and other fun items. These things cost money, however, and a teacher's budget often doesn't lend itself to fun extras. Throw in a few sets of holiday stickers, markers and a packet of blank note cards.
Every teacher will tell you that she can always use more books for her classroom library. Choose holiday-themed picture books or even a few chapter books from a grade-appropriate series, such as the Magic Tree House for second-graders. Avoid books that tell a teacher how to teach or something similar.
Throw in something personal. If your child's teacher loves coffee, include a Starbucks gift card. If she loves to garden, add a small potted plant. Gift cards to teacher supply stores or office supply stores are also always appreciated.
Make it look nice. Finish off your basket with some tissue paper and pretty ribbon, and include a note of appreciation from you and your child. The teacher will surely appreciate your efforts.