RESPECT should lead the classroom!
When students enter the classroom the primary concern is "YOU" the teacher. The students want to know you personally and the classroom environment. The classroom should begin with the word respect, especially in middle school. The line drawn is when the teacher talks the classroom is quiet. Once the students learn your expectations are to respect themself, the teacher, and the classmates. The problems sholudn't occur as often. Keep structure because students love it. A big complaint I heard was feedback that the students had more respect for the teachers that was organized and planned assignments with deadlines. Stand with a stiff backbone and the students will respond alot better to you and your teaching.