When it comes to written language, one of the biggest issues I have come across is the ability for the message to become misinterpreted. If I am speaking to a employee about a task I want done I can tell, via body language, if they understand what I want and need done. The same does not hold true in a e-mail with the absents of face to face interaction. One tip I find incredibly helpful is giving your e-mail or blog post a once over before sending it out. Read the message before sending and it will help you determine if it sounds proper and reads like you wish it to come across. Watch the video below for more tips I have picked up over the years for effective written communication.
Elements for Blog Post #2 - http://www.youtube.com/watch?v=eJLA8KnhQLE