These are good general ideas folks. But, when it comes to things like 'not blaming' or 'keeping your voice calm'...what specific things would you do to accomplish this? In reference to the calm voice thing, if the person (regardless of whether it is a fender bender or an antagonistic party goer or what ever) how do you make sure 'calm voice' doesn't spill into 'patronizing' or 'talking to him/her like he/she is an idiot...?' - which will actually escalate a situation.
DICLAIMER: THis is going to be Paul linking teacher talk to self defense so turn up your head phones if you don't want to pay attention (as the students try to do regularly

).
I use this thing called the 6 writing traits + presentation that translates nicely to this 'verbal judo' situational tool IMO:
1.Idea
2.Organization
3.Voice
4.Word Choice
5.Fluency
6.Conventions/Grammar
PLUS
Presentation
1. What is the main point of your communication: Getting information, getting out of there w/o getting hurt, getting the other guy to leave..... what is the purpose?
2. No matter what things fall into intro, body, conclusion elements. What are you going to do to 'set up' your discussion/communication to accomplish your goal, when are you going to whammie the main idea, and how are you going to wrap it up?
3. Voice is usually 'formal' or 'informal' but here it might mean more than that. Should you try to sound like an authority and take charge or more 'earthy' and just 'plain folks' to make sure you are heard and don't wind the other party up even more.
4. Once you know what 'voice' to use, use words that will keep that 'tone' going.
5. Communication flow is like martial art flow. Keep/get their attention by using longer and shorter strings of communication in variation to keep their attention going where you want it.
6. In ELA class, this is usually the part where grammar and punctuation is a big deal. Translating 6traits to this means that you have to use effective pauses, eye contact, social 'conventions' of handshakes, distance, business cards that are consistent with the 'voice' you decided on earlier.
PRESENTATION: Here is where being aware and reading the other person and his/her reactions is key. As you are doing all this verbal judo stuff, you will have to be constantly adjusting your deliver based on how the he/she is responding NOT on what you think is best to do - be adaptive. If your attempt at 'formal' is getting a 'patronized defensiveness' in the other person's reaction, adjust, adjust, adjust...
This is really involved as a conceptual structure, but it is just a way of observing the flow process of trying to get out of there with words alone. My point in applying this to my Self Defense is so that I can say "Oh, maybe my voice/tone" isn't working here, adjust it. Or "I am using words that are not working (either because of a lack of comprehension or causing some 'snooty' message that isn't intended)," adjust it.
Its just a tool to identify where and what needs to be changed quickly by recognizing which 'category' the mistake fits in and pulling from that pool of corrective measures. Reduces the choice flow chart IMO - therefore creating mental speed.