Thai people have a deep reverence for the Royal Family, and a visitor should take care in showing respect for the King, Queen and the Royal Children. You should stand still when the royal anthem is being played for example, in the cinema before every movie starts or at public places such as railways stations.

Visitors should dress appropriately when visiting religious shrines. Topless, shorts, or hot pants are unacceptable and you will not be permitted to enter the compound. You may wear your shoes when walking around the compound of a Buddhist temple but not inside the chapel where the principal Buddha image is kept. Each Buddha image, large or small, ruined or not, is regarded as a sacred object. Never climb onto one to take a photograph or do anything which may indicate a lack of respect.
Buddhist monks are forbidden to touch or be touched by a woman, or to even accept anything from the hands of one.

Thai's do not normally shake hands when they greet each other. Instead they press their palms together in a prayer-like gesture called a “Wai”.
Thai's regard the head as the highest part of the body, literally and figuratively. Therefore avoid touching people on the head and try not to point your feet at people or an object. It is considered very rude.

Shoes should be removed when entering a private Thai home.
Public displays of affection between men and women are frowned upon, but holding hands has become pretty normal nowadays in Bangkok.