I'm a first year teacher with some classroom management issues (novel, I know). I have a great relationship with my students, I feel comfortable joking around with them and they feel comfortable joking around with me, etc. However, I feel that I wasn't clear enough with my behavioral expectations in the first couple of days, now most days students are very talkative to the point where it's difficult for those who wish to listen to even pay attention. I am having some difficulty laying down the law, I don't want to come off as a cop or some other negative authority figure and lose the good relationship I have with my students now. Any advice for resetting the tone to make up for my inconsistent start?