I have become very comfortable with my own classroom management over the years, so I haven't had to try too hard at it lately. If you are having problems, though, or if you have an especially difficult class, you may want to try giving hints that you might be a little crazy.
Don't go overboard with this or you may get yourself into trouble. Just show enough crazy to make your students less than 100% sure that you aren't going to flip out if you get pushed enough. They might think twice about misbehaving.