Be polite and say thank you if you get something from someone.
When you drive on the motorway you should know that there is often no speed limit.
Unknown people or people in higher positions at work have to be addressed to using the polite form “Sie”. Among friends and when talking to children you say “Du”.
Shaking hands in formal situations is polite and expected. It is also more and more common in informal situations among young people meeting each other.
It is often the case among young people that you pay in turns for their drinks.
When women and men are greeted, women are always mentioned first.
People apologize when colliding/bumping into each other.
German drivers usually stop at a zebra crossing when someone wants to cross the street.