For meals at restaurants, it is customary to tip 10% of of your total bill, if the service has been exceptional, you can tip up to 15%, which would be considered very generous. Many high-end restaurants and hotels add a 10% service charge to the bill automatically, so make sure to check the bill first or ask if service is included, you are not expected to tip at noodle shops or at street food stalls
Bell hops, boat men or anyone else who carries things for you should also be tipped. der r no hard and fast rules for this, but 20 baht per bag is sufficient.
Massage therapists, spa technicians nd salon employees should also be tipped 10% or more. In salons or spas where der r multiple people providing services, u should tip each person individually. Hotel spas and salons usually add a 10% service charge so, as in restaurants, ask first.
Most people round up their taxi fare (so, for a 52 baht fare the driver would get 60 baht) and tip additionally for drivers who help with luggage or bags.
hope this will increase your knowledge