Classroom rules are a fundamental tenet of classroom management. A classroom rule chart should clearly states what is expected of students. Focus should be on "what to do' as opposed to "what not to do". In the classrooms that I have been in, class rules were hung in a central area in the classroom, and served as a reminder to students.
At the beginning of the year, it is important for teachers to establish what is good behavior and what is bad behavior. Students should take part in creating the classroom rules.