Tipping in America
Ideally, tips are given to a person who performs good service. Of course, the tip is in addition to the bill. In some situations, tipping is so common that if you don't leave one, people will frown upon it. Therefore, you should consider a tip mandatory in those situations.

Generally, a tip may vary between 15% to 20% or it can be a flat amount that is near the appropriate percent. It really depends upon the situation.

Restaurants
You may be surprised to know that waiters at the restaurants typically get paid much less than the minimum federal wage, often $2.13/hour. That is because they are expected to get tips from the customers. Therefore, please make sure to tip well when you visit a restaurant. In some places, when you receive the bill, the tip may be included automatically. Even the credit card slip where you sign the amount may have several suggested tip amounts calculated for you for your convenience, such as a 10% tip amount, a 15% tip amount, or a 20% amount.

You can either include the tip in the credit card slip itself or you can pay separately by cash.

Please note that many Indian restaurant owners don't give the tips to the waiters when you include it in the credit card slip. Therefore, it is much better to tip with cash. It is still possible in some situations that, at the end of their shift, the waiters' pockets are emptied and tips are taken by the owner or manager. In that case, there is not much you can do to help the waiter, though these situations happen very infrequently.

Of course, if no service is provided by the waiters or if everything is self-serve, there is no need to tip.

Travel
You should tip a taxi driver around 10% of your taxi fare. The taxi driver should usually help you load and unload the bags. When you approach the airport, there are porters, called skycaps, who can help with the bags. You should tip them $1 or $2 per bag. You do not tip the flight attendant, employees at the ticket counter, etc. If you need wheelchair assistance, you should tip at least $5 per passenger. At other places like a rental car center, you should generally tip $1 or $2 to whoever helps you with your bags.

When you reach the hotel, you should tip $1 or $2 per bag to the bellboy or doorman who handles your bags. Unless you are staying in a hotel for several nights, you don't usually tip the housekeeper. You don't tip the desk clerk.

Barber Shops and Beauty Salons
When you go for a haircut, beauty treatment, shampoo, shave or other similar services, you should generally tip at least 10-20% of the charges to the service provider.

No Tipping
There is no tipping required at the gas station. Most gas stations are self service. In New Jersey and Oregon, attendants fill your gas tank for you.

Unless someone helps you load bags in your car, there is no tipping required at the grocery store.