I've driven in L.O.S. on and off for more than 16 years.
Have had 4 minor scrapes - none of which I caused.
I drive a lot around BKK between Monday to Friday and comute to & from home in HH at weekends, so I guess I might qualify for an opinion or three

So - a few of T's basic rules.
1) Make sure that you have eyes up your ar5e - you will need them.
2) No matter what the temptation to have a race with some idiot in a pick up or yuppy in his series 3 BMW - dont bother - let them kill themselves.
3) Have plenty of THB 100 notes in the drivers door tray to accommodate the MIB fines - dont argue - it's not worth it - just smile, pay and go on your way.
4) NEVER assume that that 10 wheel truck you are about to pass has seen you and therefore will not pull out as you overtake. Flash your headlights before you make the manouvre - there's a chance the truck driver might see you - particularly at night.
5) Beware of 'U' turns - some drivers just seem incapable of judging your approaching speed and will often pull out in front of you.
6) Make sure your tyres, brakes and particularly your windsceen wipers / washers are fully functional - they could be the difference between you and an accident.
7) Always assume that the guy on the motorbike in front of you will do something stupid - there's a 50% chance he will.

9) When making a left turn in heavy traffic - check your LHS wing mirror - there's a good chance that ther will be some idiot there that you are about to squash.
10) Fit a pair of the cicular stick on mirrors to your wing mirrors - they lessen your 'blind spots' considerably.
11) If you have a Thai partner then they will want to festoon the rear view mirror with good luck charms and cover the dashboard top with Buddhas. Try to minimise this because IF you are unfortunate to have a serious accident these items can cause you serious damage.
12) Dont forget that trucks and buses are bigger than you - so their drivers often assume that they have right of way.
If any more come to mind I'll post them

Happy Motoring