Thai culture may seem similar to western culture on the surface, however, a lot of people travel to Thailand and don’t realize the culture is vastly different here from that of western culture. There are exceptions to every rule of course but for the most part here is a list of general rules so as not to offend Thai people and enjoy your holiday to the fullest.

1. Affection in public – Thai people in general do not kiss or show affection in public beyond holding hands. Please be respectful here and do the same. Be discrete.

2. Confrontation – Thai people generally speak softly and avoid confrontation at all costs. Please do not shout or raise your voice. If you wish to take a photo of a Thai person please ask first.

3. Dress properly – Thai people pay extra attention to be dressed properly. Please respect them for their efforts and follow their example. Thai people may not mind as much in the touristy areas and beaches however once out of these areas please dress appropriately.

4. Temples and Holy Places – When travelling to temples and holy places please show respect. You will need to wear long pants and long sleeves especially if you are a woman. Also, women are not allowed to touch Monks or their robes. Women also should try to avoid accidentally touching Monks at all costs. There are many sacred items and sites in Thailand please don’t touch or enter these places without permission.

5. Feet low/Head high – In Thailand, your head is considered high and holy and your feet are considered low and dirty.  It is considered very rude to raise your feet above someone else’s head (especially if they are older than you). Pointing at or touching something with the feet is also considered rude. Remember to remove your shoes when entering a Thai person's home or a sacred area.

6. Touching someone's head – Touching someone's head is very impolite and rude.

7. Don’t step over someone's legs or feet – In Thailand it is considered to be very rude and impolite to step over someone's outstretched legs or feet. You should walk around the end of their feet.

8. Respect for the King – Thai people have great respect for their king and the royal family and you should always show respect as a visitor to Thailand. Lese-Majesty - Thai Criminal Code elaborates in Article 112: “Whoever defames, insults or threatens the King, Queen, the Heir-apparent or the Regent, shall be punished with imprisonment of three to fifteen years.”

This can be anything from speaking badly of the king, defaming a statue or picture of the King, or writing an insulting article about the King. Please be careful as there are several cases of this every year and an unknowing foreigner can end up in Jail. The King however is a gentleman and is known to pardon silly foreigners from hefty jail sentences. But it’s better to avoid it in the first place and show respect to the Thai people as we are guests in their beautiful country.

9. Gifts for Children – Please do not distribute gifts to children as it encourages begging, but give to an established organization or village elders instead.

10. Sabai Sabai – In the Thai Language means to “take it easy”, “Relax” or more to that effect. In Thailand people and things tend to go a little more slowly, this is the way of life here please be patient and don’t expect things to happen in a hurry.

11. Do smile – Thailand is known as the land of smiles and smiles can mean many things here but try to smile as much as possible at Thai people and they will return in kind and be more friendly, making your experience here much more enjoyable.

12. Instead of shaking hands, Thais “wai” to greet people. The “wai” is a short bow done with hands held at fingertips together close to your chest or face. A proper “wai” is not as easy as you’d think, so practice a little to get the hang of it. Never “wai” someone of lower status – even it sounds like the egalitarian thing to do, you’ll only embarrass the person you’re “wai"-ing.

Thai people are very forgiving of foreigners that don’t understand Thai culture, so don’t stress too much if you get things wrong, however, they really appreciate it when you do try. If you do get something wrong be polite and excuse yourself.

Source: http://troycooper.com/basic-thailand-etiquette/