Tipping in Asia can be considered an insult, that they don't make enough money. Tourists who tip too much can drive local inflation for the next traveler.
Don't tip in hostels or local eateries, but in some of the nicer or luxury hotels they may be expecting a small tip. Some luxury hotels will add in a 10% service charge, but this does not go towards the staff. If you want to tip, do it at the beginning of the stay and you will get better treatment, and do it with the person directly.
Don't tip the taxi drivers, however you can round up to the near whole number.
China and Taiwan: You will embarrass yourself if you tip a waiter in a restaurant in China or Taiwan. In some places it may even be against the local law. They view it as they don't make enough money in your eye, and it embarrasses them.
For hotel staff you can give them a token of gratitude that isn't money.
Guided Tours in China do accept tips. If you aren't sure you can always do 10% or US$10 per person per day for the guide and US$5 per person per day for the driver.
Hong Kong: Hong Kong is more British or American when it comes to tipping, but don't be surprised if someone refuses a tip.
For dining- Give cash if the service provided was exceptional, or personally attentive to us. A lot of restaurants will add on a 10% service fee; however this does not go to waiters. If you are paying with a credit card and you tip on top of that, it still won't reach the waiter. If you want to tip, tip in cash and give it to them directly. Otherwise, 10% service charge is usually included in the bill so just round up to the nearest dollar. If you are unhappy with the service, don't round up. $100 HKD is a nice tip in nicer restaurants.
You would typically tip the valet, pizza delivery and everyone you would in the USA, except for taxi drivers usually round up the fare for you.
Japan: Tipping in Japan is considered rude and they will refuse tokens of appreciation. If a server keeps a tip is usually because he doesn't want to embarrass you. As a rule, just don't tip in Japan.
If you feel like you have to tip, put it in a small box or sealed envelope like it is a gift with a slight bow. They most likely won't open it right away. Never pull your wallet out and hand them cash.
Korea: It is not common to tip in restaurants because a 10% service fee is usually added. In Western restaurants you may round up to the nearest dollar or two, but don't do it in a Korean restaurant. Don't tip the hotel staff and only round to the nearest dollar for taxi drivers.
Thailand: Luxury hotels, restaurants and parking attendants will expect a tip; however locals will never tip each other. No one will turn down a tip, so if you want to tip, then tip. Restaurants will charge a 10% service fee, but this does not go towards the server. Give them a small tip in cash only directly to them on top of that fee. Hotel staff will expect 20 baht for all your luggage and parking attendants will expect 20 baht as well. For taxis round to the nearest multiple of ten or allow them to keep the change.
Malaysia: Luxury hotels, restaurants and parking attendants will expect a tip. No one will turn down a tip. Only Western or tourist areas expect a tip in restaurants. Pay hotel staff 1-2 ringgit for bell boys. Round your fare to the nearest ringgit for the taxi drivers.
Singapore: Tipping above the 10% service charge is discouraged in hotels and restaurants. A 10% service charge is usually added to your bill. If they are catering to tourists and they don't include a service fee, then the 10% is up to you, but don't tip more.
For services rendered at the airport, it's actually prohibited to tip. Shop clerks, servers, and baggage handlers all receive wages. At Changi International Airport, gratuity-free services range from baby care rooms to medical clinics. The same rule applies at dining areas, including sit-down restaurants in the airports.
Some people will tell foreigners to tip because of the Western culture, and others disagree. If you do tip, 5-10% is good. Try just rounding to the nearest whole number.
Philippines: Tipping is becoming more and more encouraged. Nicer hotels and restaurants may expect you to tip an additional 10% above the 8-12% service fee already added. Restaurants tip 5-10%, hotel staff 10 pesos is average, Tax drivers already rounds your fare to the multiple of five.