You want to reach a child's mind and a child's heart. You want them to absorb good values and good standards, and eventually to adopt them as their own. You talk with children. You keep making the best case you can. At the beginning, of course, you don't count on your words alone to carry the day.
Words take a long time to sink in.
So you stay on the scene yourself, or you remove the source of the trouble, or you introduce some diversion - whatever helps to restore peace and tranquility. But your words are what count. Once youngsters accept them because they make sense, then children have something of their own they can carry with them into the years ahead. There are, of course, no guarantees about those years ahead, no money-back promises should matters work out badly. Building moral human beings is a tremendous job and a complicated one.