Whatever the age, discipline involves rules that must be followed through and not just "threatened". It is not good to say, "stop or you will get in trouble". This is an idle threat and not concrete. Kids need rules and boundaries--in fact, they crave them. So, have classroom rules displayed poster- sized and review the expectations you have. These can be norms for behavior, operations and expectations as to schoolwork. There should be clear- cut consequences. First time, talk to the student one-on-one. Next, a phone call home. Next, use the ladder of referral--it could be guidance, dean or social worker. But, be sure to stick to the rules and even if you appear to be "mean" and not their friend at first, that's okay. You are not their friend, but you are their role model and teacher.