Strike the Right Tone: Make the purpose of your letter clear through simple and targeted language, keeping the opening paragraph brief. You can start with, “I am writing in reference to…” and from there, communicate only what you need to say. The subsequent paragraphs should include information that gives your reader a full understanding of your objective(s) but avoid meandering sentences and needlessly long words. Again, keep it concise to sustain their attention.
When you know the recipient’s name, sign it “Sincerely yours” or just “Sincerely”, or in the US “Yours truly” is acceptable. Don’t try anything more cutesy or friendly unless a) you know the recipient quite well and are certain you can be informal without seeming disrespectful, or b) you have a “trademark” letter ending that’s part of your public persona (and the talent and popularity to pull it off). Signature and printed name: Signing your name is a minimal assurance that you stand behind what was written.