Have you got opening lines and ending lines for the different kinds of structure that the writing could be? (i.e. formal letter, email)
Could I see what you had in mind to make sure I'm on the right lines?
I had been told to always start with "Sehr geehrte Damen und Herren" and end with "mit freundlichen GrΓΌΓen" - is that different to what you've been told?