I make them every year .. I paint the mason jars with a Christmas theme picture , but you can just layer the cookie mix into the jar without painting it and it still looks really nice.. I usually just use recipes that I have and just layer the ingredients and add a little card telling the recipient how to bake them and what they need to add..
Here is a good site that has lots of recipes and pictures of them done up so you can see how nice they look..
Have fun making them. I know the teachers will love them.