It's easy to fall into the trap of starting in the middle when we write. After all, if we write what we know (the most often-given writing advice in history), we can get so close to the topic that we unconsciously make assumptions about what the reader knows, and we leave out background or basic information he or she needs to understand. That's when you get the, "What is she talking about?" murmur from the person checking out your story.
The solution is easy and it comes from my first day in Journalism 101 back in college. The professor was telling us about ledes, which are the first paragraphs in news stories, and how to know what to include or not include to get the reader hooked. He told us to imagine telling our news story--the car crash, the council meeting, the community event--to a spouse at the end of the work day: The partner greets us at the door and says, "What happened today, hon?"
Of course, you'd start at the beginning--your love has been out of the loop, right? It was a great lesson for news reporting but is equally valuable for nearly all sorts of written communication, from the marketing piece you're putting together on your association's new education program to that report the boss wants on his desk by COB today. Your audience (your readers) don't have your specific background on the issue at hand, even if they're in your industry, and they don't necessarily know what you know. So when it comes to explaining something on paper, start at the beginning and go from there. Imagine them standing in your office door: What happened today, hon? Tell them in your head, and then transcribe it into your document. It'll force you to back away from the topic you know so well and get back to basics in a logical way so everyone understands.
Simple solution to a common problem. Beautiful, isn't it?