Service charges are generally added to restaurant and hotel bills in Berlin, making tipping unnecessary. Some of the smaller cafes and bars are excluded from this custom and it is standard practice to round up the bill to the nearest Deutschmark.
Sales or Use Tax: In Germany, a 16% value-added tax (Mehrwertsteuer - MwSt) is already reflected in the prices of most goods and services; the MwSt rate on books is 7%. Tourists living outside the European Union are eligible for a refund for most of the tax paid on gifts or souvenirs. Make sure you get a Tax-Free form from the store at the time of your purchase. This form should be filled out with your receipt attached. At your final departure from the European Union you must show the completed forms and the items you purchased to customs authorities who will stamp the documents. (Do not put the corresponding items in your checked luggage.) You can then claim your refund immediately through the private company Europe Tax Free Shopping, which has offices at all airports, major road borders and ferry stations. If you forget to collect your refund immediately, you can also mail your forms, with proper customs stamps, to Europe Tax-Free Shopping Processing Centre, Trubelgasse 19, 1030 Vienna, Austria.
Service charges are generally added to restaurant and hotel bills in Berlin, making tipping unnecessary. Some of the smaller cafes and bars are excluded from this custom and it is standard practice to round up the bill to the nearest Deutschmark. The cost of service should be clearly stated and visible in brochures or on menus.
Tipping is quite hard to follow. It's supposedly included in the price of the meals but you can add extra to it. There is a huge differance in opinion depending on who you speak to about what you should tip. Being American, I felt it was very cheap for me to tip 10%, but it is considered very generous there. So do what you think is right. The dollar was very strong so it's easy to add a nice tip.
Tipping: 15% at least is tacked on to your dining bill, above that is up to you, pay for the service that was provided (sometimes it is REALLY rotten, usually quite good and then there is the OUTSTANDING!).
Do not say how everything is better in your home country, no need to have a loud voice, no need to 'flash' large amounts of cash, credit cards or jewelry, in other words 'Do not make an ASS of yourself!'
Do not make comments about the people, thinking that they do not understand you, many of the people in Berlin speak more that one language, English is quite high on the list.
In general, try to behave as you would want to be treated.