Correct management of your classroom is imperiative to a successful learning enviornment. If you allow your students to behave in an unprofessional manner,this behavior impacts the other students learning experience as well as their own.Since I deal mainly with adult learners, I open my rules explanation with,"since we are adults, I do not feel we will experience any unprofessional behavior". If someone starts talking during a lesson, I will say, "We have a limited amount of time to share this important information and I, as well as your classmates, need your full attention. If this is not successful, I will have the student remain after class and will address the matter as needed.