Teachers in middle school classrooms truly have to pick their battles. A never-ending battle I have seen over the years is kids saying mean things to each other. Instead of writing a referral every time a student calls another student stupid, dumb, retard, b%#*&, or homo (sorry for the strong language, but we all know it happens), I have them pull a kindness card instead.
Once I hear a student say something mean to another student, I simply point to where the kindness cards hang on my wall. There is a little eye rolling, but they typically walk right up to the cards, pick one at random, and read aloud to the class what they must do. The other kids in the class LOVE this process. They don't want to be the person who has to DO what is on the card, but they love watching someone else do it.
Students must complete the task on the card before they continue working, but the teacher can continue teaching the rest of the class.
Tips: Print the cards on cardstock. Make sure the students know that they need to complete the task within 5 minutes. I suggest having a special desk in the classroom where they must sit in order to complete the letter (if they pull a card that requires them to write a letter). I say this because when I have allowed students to stay sitting where they are, they tend to get distracted and take too long to complete the letter. If they write a letter, NEVER let them deliver it. I always read it first to make sure it is presentable, then I (or another student) hand delivers it. Letters to parents can be mailed home. If a student refuses to do what is written on the kindness card, then a consequence should be given (such as detention, a phone call home, or referral - depending on the progressive discipline plan at your school).