Laugh and be happy
In response to Steven at the end of his tether (Ajarn Postbox 26th December 2012) First and foremost have fun! Laugh and be happy, if possible, all of the time (before, during and after school). The kids will notice when you adapt to the culture, which will make them more comfortable with you and that takes months and years to accomplish. But, until then, try to apply the advice offered to you by experienced staff. Try to empathize with the different groups of students rather than to each individual student. Get your students involved in the lessons and be sure to keep them brief. Learn from your students and Thai staff. Be a good listener. Never be rigid and always be flexible. Don't give an opinion unless you are asked for it by another teacher.
As you've lived here a few years you will definitely have a better handle on what it is you got yourself into, and by then none of this will even matter. If I knew all the crap I was to go through five years ago I may not have stayed. So, relax. Don't ever be serious. Laugh. Try not to reflect too much. Have a soft voice and softer heart. Be patient. Don't take the job personal by seeking approval from western perspectives, or try to justify being a teacher defined by a western vocabulary - ewwwwwwwwww.
Keep these tips in mind and no matter what happens, there are lots more teaching jobs available in Thailand.
DJ