I've been around too long not to believe in the law of business karma. Per the clich�, what goes around comes around. Outside a flea market, it's a rare deal when the two sides never cross paths again. So think twice before you adopt a scorched-earth strategy--you never know when you'll need a favor from the opponent you just turned inside out. Also, the more a deal is in your favor, the more the other side will look to wiggle out of it.
You don't have to be terse, rude or argumentative to win your points. Rational conversation works just as well, if not better. One of the easiest ways to build trust is to simply listen. I am constantly amazed at how easy it can be to make a deal once you understand your opponent's real concerns. The converse is also true: Your opponents are more likely to concede if you can clearly articulate the reasons behind your demands. People have a natural tendency to reciprocate. Be fair, and most people will be fair to you.
When you do cut the deal of your life, be a good sport. Don't gloat. Give the other person a chance to save face. Talk about how times have changed. Refer to some objective standard of fairness. The best deal-makers know how to get what they want but let the other side feel like a winner, too.
A speaker and attorney in Los Angeles, Marc Dieneris author of Deal Power.