One of the simplest ways to say thank you is to pen a handwritten note which is from the heart. Speak to specifics of your appreciation. Maybe the teacher helped your child through a difficult lesson or through a difficult emotional time dealing with other students. Whatever the case, be clear as to why you are thanking her and genuine in what you say. You can also mention how much your child appreciates the teacher as well.
Instruct your child to write a thank-you note to a teacher as well. Even if the child did not always get along with the teacher but ultimately became a better student because of the teacher, it is important the child makes that connection. Direct your child to write a few kind words and sign his name alongside your name thanking the teacher for all of her efforts.
If you wish to show a sign of thanks in the manner of a present, purchase a gift card to a local retail store, online store or restaurant and place it inside the thank-you note. The gift-card denomination does not have to be much, $10, $25 or $50, but will help demonstrate how much you appreciate all of the teacher's hard work. Tailor the gift card to a place where you believe the teacher shops or eats.
Teachers often decorate their rooms to make the classroom a little more inviting than just a white board with a bunch of desks. Give the teacher a plant or rooted flowers along with the thank-you note. That way he will have something to decorate the room with and think of you and your child each time he notices or waters the plant. If your child is being taught by a team of teachers working together, you can give them different plants or arrangements so that there is some variety among thank-you gifts.