It may not be customary to tip where you come from, but in America and especially in New York City, people who work in service industry jobs are often paid less than minimum wage and they rely on tips to pay their bills. Below is a guide to what you should be tipping these people if they provide a satisfactory job for you. If they were really outstanding you should tip the highest amount listed or even a bit more. If they helped to make your trip memorable, let them know that you appreciate their service!
Waiters and waitresses 15-20% or double the tax on the bill which comes to about 18%.
Taxi drivers 15-20%
Bellhops $1-2 per bag
Hotel maids $2 per day
Doorman who helps you hail a cab $1-2
Hotel concierge (dinner reservations, theater tickets or tour arrangements) $3-5
Bartender or wait staff minimum $1 per drink
Tour guides minimum $10 per person