I was taught (several decades ago) to write a capital D for all pronouns such as Du, Dir, Deine, when writing to my German penpals. I am afraid it would look antiquated or very formal these days. Is ...
Formal letters almost always used to start with "Sehr geehrte Damen und Herren," or "Sehr geehrter Herr Maier" if the person is known. However more and more we see formal correspondence that addresses ...