I am a firm believer that if students know exactly what you expect of them and exactly what will happen if they don't meet your expectations that your class room will run a lot smoother.
A "discipline hierarchy" is one in which you have a list of 3-6 consequences for breaking your rules or not meeting your expectations. Each time a rule is broken during class there is a consequence that is more punitive or restrictive than the previous one.
These vary according to your style and school policies but mine were usually something like this:
The first time a rule is broken I'll say, "Johnny, you have a warning."
2- Stay after class.
The second time a rule is broken I'll say, "Johnny, I'll see you after class."
3- Step outside and phone call home.
The third time a rule is broken I'll say, "Johnny, step outside."
4- Go to the office. (This will include a phone call home.)
The third time a rule is broken I'll say, "Johnny, now you may go to the office." This might happen if I have told a student to go outside and they argue.
*Severe clause: I reserve the right to bypass steps 1-3 for certain behaviors.