Shaking hands: Germans are great hand-shakers, and they like to do so both when arriving and when departing. It is common for a person who is joining a group to shake hands with every single individual.
Drinking: Beer and wine are part of a normal dinner and alcoholic drinks are usually offered to guests. Not drinking, however, is completely accepted. Do not insist on alcoholic drinks if a person has rejected your initial offer and don’t order them for them. A German who rejects a drink is not just being shy or polite but does not want to drink. For some cultures it is uncommon to see teenagers order a beer at restaurants and pubs. Remember that the legal drinking age in Germany is 16 for beer and wine and 18 for spirits.
Punctuality: Don’t turn up late for an appointment or when meeting people. Germans are extremely punctual, and even a few minutes’ delay can offend. Be five to 10 minutes early for important appointments and be sure to call the people you are meeting if you really cannot make it in time.
Du and Sie: In private, the older person suggests using the informal "du" to the younger person. In the business world, the higher ranking person–regardless of age and sex–would always be the one to suggest switching to "du." A nice intermediate step is to address a person by their first name but then use the formal "Sie." Always ask, however, before you decide to take this step. If you’re not on a first-name basis in German, you can still switch when speaking English. But don’t forget to switch back.
Titles: Titles of nobility belong to an individual’s name–such as Fürstin von Metternich. When in doubt, it is advisable to ask. Academic titles also belong to the name, such as Herr Doktor Müller or Frau Professor Weise.
Flowers: Bring flowers if you’re invited to a German home for some social occasion. If the flowers are wrapped in paper, remember to take off the wrapping just before you enter the home.
Garbage: Germans are extremely environmentally conscious and separate their garbage to facilitate recycling. If your neighbors spot you throwing recyclable glass or paper into the regular garbage, your relationship could be strained for good.
Kissing: When close friends greet each other, it is common to kiss both the left and right cheeks. However, this is considered inappropriate in a business setting.
Silverware language: Crossing the knife and fork on your plate is an indication that you are not yet finished with your meal. Placing knife and fork on the right side of the plate in parallel is a signal to the waiter that you have finished and that the plate can be cleared away.
Knocking: When entering an office, it is common to knock first and then enter the room immediately.
Names: It is polite to address everyone by their family name and "Sie." Do not leave off double-barreled names, such as Frau Müller-Weber. Names are inserted into conversation after every few sentences.
Birthdays: You do not have to throw a party for yourself, but if you do, provide food and drinks for all your guests. (In return, they’ll give you presents.) It is also common to bring some cake for your colleagues on your birthday.
Closed doors: Germans enjoy quietness and privacy. They may thus often close their doors but will be happy to receive you if you knock on the door. A closed door doesn’t necessarily mean that the person cannot be disturbed. Likewise a closed bathroom door in somebody’s house does not mean the bathroom is occupied.
Telephoning: Don’t call people at home after 10 p.m. unless you’ve asked them first if it’s all right. Don’t expect to reach anyone in the office after 5 p.m. Monday through Thursday and after 4 p.m. on Fridays. When answering the phone in Germany, it is common to identify yourself with your last name.
Fräulein: Forget this outdated form of addressing young women. These days, rather than being seen as polite, it can be offensive. Just use the normal "Frau Müller."
Nudity: In Germany, you might be confronted with a much more tolerant, open attitude to public nudity than might be the case in your home country. Saunas, a minority of swimming pools and even some public parks on sunny days are considered to be "textile free," at least at particular times. Getting together completely naked in a sauna, however, has no sexual dimension to it whatsoever. But if you feel you would be uncomfortable, it may be a good idea to ask first before you join a trip to the pool. This attitude spills over to television, where the programs and even the commercials can feature more nudity than is the case in most countries.
Greetings: When customers enter shops, especially smaller outlets, they greet everyone in the shop. The same is true of doctors’ waiting rooms. So practice saying "Guten Tag" and "Auf Wiedersehen."
Seating in restaurants: It is common to share tables with perfect strangers when restaurants are full and very busy. Before you do so, however, always point to the free seat and ask, "Ist dieser Platz noch frei?" (Is this seat free?). Also, wish the other diners at the table "Guten Appetit." But don’t expect any further conversation at the table. It may be very welcome, but you shouldn’t force it. When you leave, be sure to bid farewell to your table companions.
Toasting: It’s common to clink glasses with a "Prost" ("cheers") or "Zum Wohl" ("good health") before drinking. At official dinners, it is more common to lift the glass by the stem and nod meaningfully to the others. The host should lead the toast. At a dinner party or in a restaurant, you should not start eating or drinking until everyone in the group has received their drink or their meal, and then follow the lead of the host.