It is good to leave a little on your plate. If you eat everything, it means you want more.
People always offer you more food. The host will ask you two or three times if you want more food. First, you must say no. Then the host insists again, and you must say no again. The host insists a third time and you finally say yes and take a little. If you really don’t want any more, take very little and leave it on your plate. It is the same with whatever you are drinking. During the meal, never empty your cup or glass. When it is less than half full, your host or neighbor will refill it. Never fill your own glass. Always refill your neighbor’s glass. This means that you must keep an eye on your neighbor’s glass all through the meal.
The most important place at a table is at the middle. An important guest will sit at the middle of the table on one side, and the host will sit at the middle of the table on the other side. This may be confusing when the table is round, but the Thai get it right somehow