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.
For instance, in a typical job application, the problem is that the company or organization needs a position filled, and more importantly they need someone who can do the job well and help the organization achieve its mission (which may be more profits, or it may be to save children in Darfur or to end global warming or to cure cancer). You arouse their interest by telling them that you’re the right person for the position and by promising to help them achieve their mission.