We have a behaviour unit of sorts, which I happen to work in 2 days a week, don't need to beat them, it usually works if you can out talk them, out bravado them, basically verbally put them in there place. But the trick is not to belittle them or pick on them, otherwise you lose their respect. And to be honest 90% of getting difficult students to do things they don't want to do is all down to mutual respect. I don't shout or yell at students, if you do you've already lost as you've got no where else to go. I just tell them how it is. And yes apparently according to friends and family I supposedly have the patience of a saint.