Carl Zimmer just gave a short talk at SciFoo on 3 rules for making sure your research is understood:

1. Mentalize - Try to get inside the head of your reader (someone without your knowledge) and see what you are saying through their eyes.
2. Choose every word - No jargon. Carl's list of banned words is useful for avoiding jargon
3. Take stories seriously - People think in stories - use them in communicating. Make sure your talk hangs together