It is important to be upfront with the students on the first day of class as to what the expectations of them are. I review sections of the student handbook and make sure each student has a copy or the website of the online version. I keep a copy of the student handbook available in the class hallway and in each classroom. A rereview of the dress code is done midway through the class and a quiz on the student handbook is done the last week. As adults the students appreciate knowing what is expected. I have noticed that at times the class will self correct itself or will quiet the disturber. This tends to be well received by the disturber. What efforts do you make to ensure the students know what is expected of them?