Thailand is known as a hospitable and tolerant land, and I'm sure you will have no difficulty in adapting to local customs. Like other countries, however, Thailand has its own time-honoured social costums and traditions that all Thais people respect. The following tips are mostly common sense, but to avoid giving offence, you may find them useful:
1) When addressing a Thai person it is polite to use just their first name. In more formal situations you should use the world "Khun". This is like "Mr" and is used for addressing both men and women.
2) To lose one's temper, especially in public, is regarded as bad manner. Nor does it achieve anything. The best advice is always to keep a sense of humour and smile.
3) It is not usual to shake hands when you meet a Thai person. Instead you do a "wai" - you put your hands together as if you are saying a prayer, and bow your head slightly. You should always use this greeting when you meet older people.
4) Couples should be careful about how they behave. You don't see Thai couples kissing in pubblic.
5) The head is very important in Thai culture. It is not respectful to touch another person's head.
6) If you're invited to someone's home, you should always take off your shoes. It's very important to remember this.
7) When eating a meal with Thai people, you should expect the food to be served in large bowls in the centre of the table. Everyone helps themselves, using a spoon and fork.
8) Don't touch a Buddhist monk if you are a woman. Monks are sworn to celibacy and are forbidden from even the slightest physical contact with a woman.
9) Mai Pen Rai: Thai phrase which means never mind, it doesn't matter - a concept well worth keeping in mind.
10) Finally, you should never insult the Thai royal family. Thais always show respect towards their royalty, and they expect visitors to do the same.
See also my Bangkok diary