Set up a pamper room in the teacher's lounge. On their breaks teachers can get a shoulder massage or hand treatment.
Have students bring their teachers cards of encouragement thanking them for all they do. Ask students to create their own cards.
Set up a dessert bar complete with coffee and drinks that teachers can enjoy after school on a certain day. If they don't want to stay let them take the treats home.
Set a day aside that all teachers can come dressed casual. Make the mandatory dress that day jeans and t-shirt.
After school while teachers are working in their rooms or tidying up play some of their favorite songs. Put together a song list by asking all teachers what their favorite songs are.