53 - Use happy and sad faces. In classes of young students you can draw two faces at opposite ends. Like this..
Pablo
Jessica
Sara
Pablo and Jessica are behaving well and Sara has done something wrong. I was dubious when someone told me to do this but it works very well. My students are always trying to get a happy face and their bahaviour improves when you give them a sad face.
Don't overuse the sad face, if you do, it soon loses it's power!