Well...........
1. Ask them to wait a moment while you take off your jacket and roll up your shirtsleeves. When they ask what's going on tell them
"Well we are obviously heading for a fight. I'm just getting prepared"
2. "For your comments to be insulting, I would need to care"
3. Practice your Glasgow kiss on a watermelon.
4. ....................but seriously.
5. Try and remember that if you lose your temper, you often lose the argument.
6. Let them rant on, remain passive but attendant. Gently nod your head to acknowledge each point raised. When they finish and hopefully calm down a bit, respond to their grievances.
7. Be aware of your body language. Do NOT fold your arms, point your finger, swear or raise your voice.
If all this fails, kick 'em in the nuts and run.
8. Try and edge yourself out of his personal space, normally at least an arm's length.