Another piece of advice that I got for dealing with bad children I think helps more with older children.
I had a friend who was a high school English teacher, who was teaching in a juvenile detention center. She was dealing with children who were criminals, so those youngsters were pretty bad. The way she said she dealt with it was to be friendly toward the worst kids. When a teenager has gone all through school being hated by every teacher they ever had, and they finally have a teacher who likes them instead of hating them, it's quite a shock! And then they'll do everything they can to help that teacher out. Not only would the behavior improve, but she would also get a fantastic helper at the same time.
At the daycare I was working for, there was a 4th or 5th grader who had a reputation for being the worst-behaved kid in the school. (I never got any of the details, but I do know that some horrible things had happened to him when he was younger.) He wanted to be seen as tough and bad and rebellious. He even spent quite a bit of time in a mental hospital because of his bad behavior. But instead of hating him as a trouble-maker as all his other teachers did, I decided to like him instead. And that was the last thing he was expecting.
Once he was aware that I really liked him and didn't hate him like all the other teachers, the drastic change in his behavior was incredible. He went from being the biggest trouble-maker to being the most helpful child I have ever worked with.
A few times I brought in a video game for the kids to play (this was back in the days when video games were just beginning to get popular, and most kids still didn't have any). To help keep the kids from fighting over who got to use it, he wrote up a schedule and organized whose turn it would be to play the games and when. There were no fights and all the kids waited patiently until it was their turn, and everybody was happy. Another time the kids decided to put on a magic show. He organized and ran the whole thing, and everybody had a good time doing it. He had a little brother who was also a serious problem, but whenever he was there (when he wasn't in the mental hospital) he would always help keep him under control for me.
Plenty of times I would just sit back and let him run things, and he did a great job and I'm sure he felt very proud of himself with what he could accomplish to help. I would always tell him how much I appreciated all his help, and I knew that was why he became so good and helpful. Any time I needed someone I could depend on to do something important for me, he was the one I knew I could count on. He even dropped his tough guy persona. And it was just because I didn't hate him and look at him as nothing more than a trouble-maker.
I just wish I had been more successful at changing his behavior everywhere; he never got any better when he was anywhere other than with me. I don’t think anybody ever took me seriously when I said how good he was with me. I wish I could have convinced them of what that boy was capable of when he was treated with respect and appreciation and was liked, but nobody believed it.
It is amazing what happens when a child who has always been hated by adults meets one who actually likes him. That piece of advice also served me well as another good way to deal with an extreme behavior problem.