You'd be lucky to be in Thailand. But you must remember some rules because it another country and there are some law which you can't ignore. At first you should know that you mustn't speak badly about Buddha and Buddhism. Also you will have to take off your shoes beforehand comming into the temple. You must respect religious customs.
There are many places to go in Thailand. For example you can visit a Thai massage session. It will be much longer than another session you have had. And it should be very pleasant. Also you should try Thai meal. It's delicious but if you don't like spicy food you have to say "no spicy" and your stomache survaves if necessary it could be burned.
Usually some tourists try to copy thai gesture of greeting "wai". Even if you really want to respect to somebody you must avoid bows with folded hands. Otherwise you may accidentally offend somebody. Also if someone offers you to try some treat you don't have to refuse. It will be better to try it just a bit than refuse at all. Еven if you aren't hungry. Just try it a bit. It would say about your good manners.
Thais are very quiet people. So you should be peacefull and calm. You don't have to shout, damn, abuse, argue, еven if you used to do everyday in your usual life. Otherwise you risk to be misunderstood or sometimes actually ignored. You should better be ralaxed and enjoy life. You arrive to have a rest, don't you?
Some people in Europe or in Russia too, love patting someone's children heads or friends. In Thailand head is most important part of the body and touch it would be wrong. If you accidentally did it, you must politely apologize. You have to do everything very sincerely and people who would be around - understand you and forgive you, because you are just a tourist. And they know about it.