This was how I handled my class. They made class rules and then we posted them. We had a basket in the center of our table and each time someone did something good, i.e., following a rule, I put their name in the basket. At the end of the class, we drew a name and that child got to take a gift from the gift box. The kids that were well behaved, had a better chance of getting their name pulled.
Positive reinforcement works great.
I did this with 3rd and 4th graders and now the 1st and 2nd grade class is trying it. One of the their students read their rules before each class. It helps if they make their own rules. It also makes class fun. One year we had a very hard to control group of boys.