The German etiquette is rather formal. To welcome each other, you shake your counterpart’s hand and address him with “Sie”, a formal you. The less formal “Du” is usually initially offered by an older or superior person. Younger people are often less complicated and talk more colloquial.
When answering the phone you introduce yourself with your last name; or when you are at work, with your last name, the company’s name and the department you work in. Starting a conversation with “Guten Tag!” (Good day) and ending it with “Auf Wiederhören!” (Goodbye) or “Tschüss!” (Bye) is always a good idea.
Germans put a lot of emphasis on punctuality. No matter if private or business appointments, you are expected to arrive on time. This is especially important in your work life.
It is less problematic to be a few minutes late or early in your private life. If for example you scheduled to meet with your friends at 10 o’clock, you should best arrive between 9.55 and 10.05.