Talk to other people near you and ignore whatever they are doing. They won't bother u as much if they see your like taking notes or something. Also whenever they do something glare at them for a second ( if your good at it) and eventually they will get the message... hopefully.
If someone is annoying you, don't let them see it, ignore them and enjoy yourself. The more you think about it, they will eventually leave you alone. So the best thing to do is to simply look the other way and don't reply them.