Remember: European hotels and restaurants and all-inclusive resorts usually have the gratuity added in to the bill. Don't double-tip … unless you feel extremely free with your money. Back here in the States, the guidelines for filling those outstretched hands are as follows:
Waiters/waitresses: 15 to 20 percent of the dinner bill, depending on the service.
Coatcheck. A dollar or two a couple.
Restroom attendants. Fifty cents to $1.
Bartenders. A buck a round, if it's just you and your wife ordering drinks.
Wine stewards: 15 to 20 percent of the wine bill.
Buffet servers. A dollar or two per person if the service has been good.
Room service. Check the bill when you sign for your order — often, the gratuity will be added to the bill. Otherwise, 15 to 20 percent of the total.
Bellboys: $1 a bag; $1 for opening the room; $5 for sending him on an errand. (Adjust this rate to the city. In New York or San Francisco, up the tip a bit.)
Chambermaids. A dollar or two a night.
Concierge: $5 to $10 for booking reservations or securing theater tickets.
Valet: $2 to $3.
Maitre'd: $20 to $100, depending on the restaurant, depending on how badly you want to eat there, and depending on how long you want to wait for a table.
Doorman: $1 to $2 for hailing a cab; $2 to $5 for helping with bags.
If you're headed off on a cruise, you're entering an entirely different tipping environment — the good news is that each cruise line will provide you with tipping guidelines.
About.com also has a great global guide to restaurant tipping etiquette that you should check out if your honeymoon takes you outside of the U.S.
Remember: Tipping is always voluntary — but if someone really goes out of their way for you and your bride on your honeymoon, make sure you reward them appropriately.

