This is great stuff from the HBR blog:
In this era of double-digit unemployment, many of us are either job-hunting or helping friends and colleagues who are searching for employment. After crafting a cover letter, set it aside, do something else as a distraction, and then return to it with fresh eyes. Imagine you are the hiring manager and this has landed on your desk or in your in-box. Does the letter capture your attention from the very first moment?
Think about the audience and talk to them directly. Link to full blog: Effective Communciation Begins with a First Impression