This is an interesting way to keep order in a classroom. Basically you find out from your Director of Studies what the usual punishment in the school is be it detention, lines, expulsion from the class, calling parents, etc.
Next, prepare a couple of cards: one yellow and one red.
Now, in the classroom use these like a football referee does. A yellow card is a warning and a red card means it’s over for the student. You need to be firm with this one but it works.
Useful Links
Discipline in your TEFL Class