One has to remember that schools are places students go to learn. All students need to learn to appreciate each and every person. Gender, race, religion, or age should not matter. The teaching of a deep respect for humankind would eliminate violence. Conflicts would be eliminated through acceptance.
Example is life's best teacher.
Look at the television shows and video games available to children today. Teachers could instruct their students about the practice of boycotting products to eliminate them from the market. Television shows could be rated for violence and the results sent to the television producers with some suggestions for alternatives. The same could be done with video games. Teachers can even have students develop their own video games, television shows, books and more, focusing on non-violence.