Don't bother. In today's schools, most little pricks know they can get away with it, because if fists start flying from the other guy, suddenly you're the devil incarnate. The problem is that most kids and teenagers, due to this, don't understand anything but a good whack in the face, but due to annnoying parents and whiny lawsuits, this can't happen anymore. Point is, being honest, teachers are useless when someones bothering you, and you can't do anything about it, because you're somehow instantly worthless and scum.
Step 1: Ban all fisticuffs in schools.
Step 2: Condition children to know they can get away with anything they want, because words don't work anymore and fists aren't allowed.
Step 3: ??????????????????
Step 4: Profit!