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.
How do you know for sure whether or not to use a closing? One good test is to ask yourself whether this email is more akin to an instant message/text or a business letter. If you're giving your teammate a quick update on an ongoing project, a formal closing might not be necessary; if you're throwing your hat in the ring for a promotion, it definitely is required. When all else fails, and you're still not sure, err on the side of caution and include it. You'll never go wrong by being too polite and respectful.