Greetings tend to be quite formal in Germany even between friends. It’s usual to shake hands say Guten Morgen (Good morning), Guten Tag (Good day/afternoon), Guten Abend (Good evening) or in more informal contexts, Hallo (Hello). You add the person’s name with their titles, e.g. Herr/Frau (Mr/Mrs), if you know them. If someone has several titles, e.g. Herr Doktor Professor, use them all.
Until you know someone well, it’s a good idea to stick to the formal form of address (Sie) and language. However using the informal Du for you is becoming more common, especially among people under 30. First names are usually only used when you know someone well, or in informal situations, such as at parties.
When you go into a waiting room or a lift, or if you’re sharing a table with someone, it’s usual to exchange greetings with them. Greeting strangers on the street isn’t customary, but doing so when walking in the countryside or mountains is more common.
The Germans enjoy talking about politics and are not being rude if they ask you direct questions about your political views. They also tend to speak their minds about other people, rather than using white lies or euphemisms to avoid hurting feelings, as is more common in the UK. They prefer not to talk about money and financial matters though.
When eating with other people it’s considered rude to start eating before everyone has been served, and you usually wish the other diners Guten Appetit before getting stuck in. Using a knife and fork rather than just a fork is best in formal situations. It’s also considered polite to place your wrists or forearms on the table, though not your elbows.
If you see a bell in a German pub, don’t be tempted to ring it unless you’re prepared to buy a drink from everyone there.