1- No Eating
2- If I am talking you are listening.
3-No mobile phones.
1 warning- your name in my book. 2 warnings- your name to your head teacher. Make sure the rules are in English and Chinese so they cant say they didn't understand them!
I have never got to 2 warnings as 1 is enough if you follow and carry through on your threat.
Something else I do in my first week is find out who the monitor is and write a brief description of him/her and where they sit. They are a great person to have on your side as they know all the kids in the class.
Peer pressure is a great tool too. Give them a carrot, explain the lesson structure " we will do this and if we get it finished this is what will happen." My kids all love games and videos so this is the carrot. If they don't finish the work they don't get the rewards. If you have a few disruptive students make sure the class know who is at fault because the whole class will miss out on the 'carrot'. Losing face in front of their peers is enough to make them behave and work. In a class size of 80 you cant win em all and some of them will not work. Explain they can sit quietly and not disrupt the class. If they do, the warnings will occur. You will find they will join in when they realise how much fun it is!
As for them Ganging up on the teacher, be very careful this doesn't turn into a war as with some students they will not back down in front of their mates. It is easier for you to shrug your shoulders, turn off your computer and just sit for as long as it takes, even all lesson. Someone in that class (most likely the monitor) will tell their head teacher. Apologies will follow... lol