Construct a conflict resolution plan. Research ways to calmly and pleasantly resolve a fight before it gets physical. For example, plan to get the students who are fighting to sit down in a neutral place and talk the problem out. Be clear that both parties will be allowed to speak and that you will mediate the discussion.
Outline penalties for students who disobey the rules or are violent on school grounds. Detention, suspension and contacting parents are some of the traditional punishments. Make these clear and uniform.
Share the conflict resolution plan and the punishment plan with students and be clear so that they understand that violence will not be tolerated, and that there are alternatives to fists for resolving anger issues. Explain that violence is the least effective way to solve problems and resolve conflict.
Develop an anonymous system by which students can report others involved in violence. An open-door policy allows students to talk to an adult who they feel they can trust when they are angry about something. Sometimes violence stems from students not feeling as though they have a way to express their issues with people.