Create a homemade card that your preschooler can color or paint. Purchase a plain ceramic mug and hand-paint it with the appropriate type of paint. A craft store can tell you what type of paint to use. You can also design a mug from Snapfish.com or Shutterfly.com with a personalized picture of your preschooler and his teacher.
Organize a special breakfast for your preschooler's teacher. Coordinate this with other parents and bring in pancakes, breakfast casseroles, bagels and muffins. Don't forget the coffee, any teacher's best friend in the morning. While this will take some extra effort, it will make him feel special and much appreciated. For something simpler, send a small breakfast just for him. Wrap a small loaf of banana bread in cellophane and add a hot chocolate packet. Place both in a small gift bag. Another option is to send a plastic or glass container with cereal and granola along with a personal milk jug.
Let your child bring her teacher a gift one morning. Send an apple with a gift certificate attached for either a spa, coffee shop, shopping or her favorite restaurant. Another option is a plant with a special message that she can keep in her classroom. You could even plant a tree in her honor.
Create a project that every student participates in. Have every child color a picture on the same size paper and make a booklet out of it. Hole-punch three holes on the left side of the pages and tie a ribbon through each hole. Another option is to record a short video of each student telling why they appreciate their teacher.