1. Think about the TEFL course you took. Was there a unit on classroom management?
2. Give them the stare of death.
3. Threaten to tap them on the top of their head.
4. Give them the universal 'shush' sign.
5. Do your best not to teach that very nasty English curse, "Shut up!" Then, when you lose your temper, they'll know you're really mad.
6. Have a penalty point system. When the kid's too noisy, give him a point.
7. Walk back to where he is. See if he's done his work. Tell him to do his work.
8. If half the class is being noisy, different story.
A. Have something like a textbook that you can slap on the desk or on the chalkboard, really hard and really loud. Gets their attention.
B. Show them that when they're loud, they get work instead of games.
9. If there's a helpful Thai teacher who speaks nit noi English, ask her.
That's all I can think of during insomnia. It's a great question, just what we need in the staffroom and classroom threads. Maybe it was covered before, but it's good to review.