Understand the listener's motivation

I think this one's especially important. Whenever I get asked a question by a functional person that doesn't make sense (or I can't fathom why they'd want the answer to the question), the first words out of my mouth are: "What is it you are trying to do?".

I've gotten a lot of mileage out of that question. More often than not, it reveals an error in the questioner's previous understanding of the topic at hand. This way, they then learn a) that they've misunderstood something, b) what question they should be asking and c) the answer to the right question.

The best communication in the world won't help your group's performance if you're talking about the wrong things.