In the October 2010 Quality Progress, there is an article by Burjor Mehta entitled "Word Power". In this article, Mehta gives 12 points for quality professionals to improve their communications in writing. I think these points are applicable for most technical people. For the details, please see the article. For convenience, the 12 points are:

  1. Use words with positive connotations
  2. Always look on the bright side
  3. Say what you want, not what you don’t
  4. Be brief and to the point
  5. Use consistent terms
  6. Use consistent formats
  7. Use white space
  8. Be specific
  9. Underpromise and overdeliver
  10. Don’t use jargon or clichés
  11. Use complete words and sentences
  12. Use "I" to ask and "you" to give