One of the best classroom management tools I ever used was having a "Secret Student" every day. I would put someone's name under this Secret Student sign on the white board (I printed the sign, laminated it, and put double-sided magnets on the sides). At the end of the day if that student worked hard, was kind, and did their job well I would reveal their name, the class would clap for them, and I would let them have a piece of candy. If that student did not have a good day I would announce that the Secret Student didn't quite make it today, but hopefully they would next time their name was there. Most of the time I would speak to that student privately at some point and we would talk about what they could've done better and I would encourage them that next time they could do it. I have to admit that occasionally if the class was having a tough time overall I wouldn't put anyone's name there and just tell them that the person didn't make it. That usually helped everyone to try harder the next day.