Customs dealing with tipping in other countries may differ from those adhered to in North America.
In Austria, many restaurants include tax and a service charge in their bills, and it is customary to round up the total when paying.
Here's how it works. Say your bill is €28.50 and you are satisfied with the service. Round the bill up to €30 and pay that amount to the waiter. You can say, "Make it 30," or simply tell the waiter the amount you want to pay when you settle the bill. S/he will probably understand English (though it's courteous to learn a few words in the local language. It pays great dividends to at least make the effort). Alternatively, you can give your waitperson the amount you want to pay (gratuity and bill, as above) and say "danke" (which means "thank you.") It's important to understand that saying "danke" when presenting your payment is the Austrian equivalent to saying, "Keep the change." If you are not satisfied with the service, it is not unusual not to tip.
In Austrian restaurants (as in many European countries), they are not in the habit of rushing people out, as in the U.S. Your bill (never a "check" which means "cheque," as in the slip of paper used to pay from your checking account) will not usually be presented to you until you ask for it. Ask for the check by saying (in German) " Zahlen, bitte" or "Die Rechnung, bitte."
Taxi drivers usually receive an extra 10 percent over the meter fare.
Porters or bellhops should receive up to €1 per bag. You can learn more on etiquette in Austria.