Let's reinterpret the familiar tale of the Three Little Pigs and their nemesis wolf in real adult terms, and apply it to negotiation.
We often tell the tale to children to help them deal with their various fears, some expressed as fear of being eaten. Adults, too, have fears, often similar. They fear being "eaten alive" by a clever and aggressive business adversary. Still, to counter the fear we need only one pig, one who is intelligent, a planner, and not panicked. And our hero pig can then build a metaphoric house of bricks to thwart the business wolf.
This is essentially what I speak of when I advocate using Zen technique, or getting to Your Zen Spacesm to counter the fear of being eaten alive or otherwise beaten at bargaining. Remember to concentrate on three consecutive breaths, the inhale and exhale; imagine yourself personally outside the situation and observing it; and practice this procedure often, at non-threatening times.
You will now be able to thwart the wolf at the door, and no amount of his or her huffing and puffing will threaten you. You will feel safe and able to think rationally and ahead.