Know Your Audience.
Following on from yesterday's confusion theme, I found this lexical density analysis of keynote speeches made by Steve Jobs, Bill Gates and Michael Dell. They were all talking about computers but did so in different ways.
People (as the comments illustrate) have their definite preferences while I can find cringeworthy material in Job's evangelism, Gates's geekiness and Dell's jargon but that's not really relevant. In all communication, you have to focus on tailoring your lexical density and style to your audience. This analysis (while very interesting) can't do that because it's objective and the whole point of effective communication is that it's subjective.