I have zero experience with this. But I learned a lot about communicating effectively under pressure while very ill and being jerked around by doctors. If I got all emotional, it was just another excuse to dismiss my very real concerns that I might die if they didn't treat me. I had to keep a very cool head at a time when that was enormously challenging due to pain, fear, how sick I was, etc. I found that doing a few minutes of "meditating" just beforehand -- breathe deeply, clear your mind of prejudices, that sort of thing -- was one of the most effective things I could do.

I would also recommend you pick up a copy of "Getting to Yes" if you aren't familiar with it. It is a quick read and research-based. A meatier book is "The Mind and Heart of the Negotiator". http://www.amazon.com/Mind-Heart-Negotiator-Leigh-Thompson/d... But it might be a bit late for that. (EDIT: Both were required texts in a class I had on "Negotiation and Conflict Management".)

Good luck.