A subject of one of my previous posts contained the quote "what is not in writing has not been said". While you may not want to make that statement to your boss when asked about your last conversation, there are many times when this statement is applicable during your project's lifecycle.
A project manager’s main function is to complete his or her project on time and on budget. This takes teamwork and a strong commitment by all team members. To be a successful project manager you must use written communications to ensure the team is kept informed.
Having said that, just because you go to the trouble to document your thoughts does not mean that your communications are clear. The receiver of your message will act on the message they think they received, which is then filtered by the receiver through their emotions and assumptions.
Don't be as concerned with what your words mean, but more with the effect they will have on the people that read them.
An important fact when writing, "Know Your Audience". If the tone of the message reflects the audience's needs you are more likely to grab the reader’s attention and keep it longer.
Most of your readers are overworked, underpaid, unappreciated, and tired of reading all the e-mails, memos, and office correspondence they receive. While this may see extreme, keep it in mind when writing your message and you will tend to keep your messages focused to the point and brief.