Dear Dennis,
I'm your classmate,and would like to talk something about our class.I think it would be impolitely to talk loudly in the halways,eat snacks in class and drop litter on the floor,and cut in line when getting on the school bus.also I think it's politely to say "hello" to our teachers and our classmates.How you think about my suggestions and I hope we can do it together from now on.
Best regards
xxx