One of the hardest things about teaching, especially if you're working for more than one school, is managing your time so that it doesn't manage you. I certainly won't lie and say I'm an expert at time management; I've been known to cut deadlines pretty close, especially in my university days. Still, being able to finish what you need to do without it interfering with your after-school life is, to me, one of the most important parts of enjoying teaching in Thailand.
Even if you're lucky like me and have only a handful of classes with under 30 students per class in a high school (and I realize I'm quite lucky), when you consider the amount of planning it takes to make meaningful lessons, set exams, grade papers, and deal with student issues, you're looking at a long day. That's not even taking into account having to deal with "office politics," last-minute administration requirements, and other "emergencies" that seem to pop up in Thai schools on a daily basis.
Taking all of this into account means you need to practice how you use your time, or else you're going to spend every waking moment playing catch-up.
I've made it a point not to take school work home unless absolutely necessary; in fact, at least with my government school, I have only had to take home papers to grade one time in almost two years. I'm borderline neurotic about it; even if I do bring something home, the chances of me actually DOING it are, well, nill.
Granted, I have to do lesson planning for all of my outside-school classes frequently, but the good thing about most classes I've taught is that they frequently overlap regardless of the class topic or title. I say, why do the same thing twice?
Thus, I have a few common-sense time management tips to offer for any of you newbies out there struggling to have a night on the town without stacks of work to be done nagging you in the back of your mind.
First, save everything. It doesn't matter what subject you teach, what lessons you plan, or what schools you're working with. Student grade spreadsheets, PDF worksheets you make/find, random word lists... save it. I can't count the number of times a worksheet or lesson from another school or class has come in extremely handy with something months down the road. If you bother typing or otherwise creating something, save it.
That said, second, organize everything. I may be the world's worst when it comes to organizing physical papers, but when it comes to computer documents (and let's face it, that's the easiest way to keep materials on hand these days), I'm as spot-on as a German train timetable. I know many teachers (both in Thailand and not) who do have what they need, but spend so long trying to find it that they just give up and remake whatever it was. I also highly recommend installing Microsoft Skydrive, Dropbox, or any other cloud-based storage solution; while I resisted it for years, there's a lot to be said for A) not having to walk back to another office to get a file, and B) avoiding hard drive crashes. I've been privy to both.
Paper-wise, I do my absolute best to make sure I don't keep any student papers any longer than I have to without returning them. It's easy to have mountains of paper pile up, so your best bet is to grade it, and unless you have a reason to keep it, give it back immediately. Even if you don't lose a paper yourself, in many Thai schools with shared offices, things are bound to get moved around with or without your knowledge. I've found accordion folders to be quite useful for those papers that I absolutely must keep.
Third, if you've got a lot to do, it may be best to hide until you get it done. I often feel bad that I'm not included in the juicy gossip of the office many days, but I feel my coworkers understand that I'd rather not have to take work home to interfere with my time with my girlfriend... and possibly happy hour. If I've worked with you before and this has occurred, well, you have my apologies.
Fourth, try to make worksheets and tests as easy to grade as possible. I'm not saying to make tests easy for students, but rather to make marking their answers easy. I've slowly moved towards a system of making little lines next to the number of questions meant for multiple choice or short answer questions; that way, when marking, I can simply line up an answer key next to the blanks and grade lickety-split. I'm sure I remember teachers giving me papers like this in school, but it never occurred to me as to the purpose until I began grading myself. Obviously this won't work for longer answers, but if you design any assignment for easy grading, you'll thank yourself later.
Finally, fifth: relax. There's nothing worse than having too much to do and not even knowing where to start. I'm sure most of us have been there and done that. At least in Thailand, I've found the best way to deal with a large workload is to take it easy, and attack one thing at a time. Sure, your desk may be overflowing with the assignments of six different classes and midterms needing grading to boot, but there's no point in stressing over it all. Just focus on one thing at a time and remember, it'll all get done eventually.
That's a really good thing to remember: no matter how much there is to do, it'll all get done one way or another. So be the best teacher you can be, and try to enjoy your free time in Thailand. A stressed out teacher makes for stressed out students, so if you find yourself having difficulty keeping up, don't worry. If you really enjoy teaching, you'll find a way to fall into the swing of things.