Never in any way shape or form should you say anything, or do anything that could be considered slander toward the royal family and the King in particular. The Thai people love their king and queen, they will defend the honor of the royal family at all times. This includes taking care of the money. Thai money has the image of the king on there and should never be stepped on or mistreated.
Never raise your voice or show your anger. The Thai people will feel that you are angry even if you speak strongly. You may not be angry, yet you will appear that way when speaking with a lot of force. Behaving in this way will cause you to lose face and will lower your status. You will have much better luck getting what you need by learning to speak with authority and humor and keeping your voice level. This will keep you from looking like a pushy tourist.
Never hurt anyone, particularly a Thai. You will be getting a visit from the police and you do not want that. There is a large price to pay when you are dealing with the law.
Finally, Thailand is known as the land of smiles, so smile a lot and have a great time on your trip to Thailand!
Please feel free to add any rules of etiquette you learned while you were in Thailand. We love to hear your comments!