Getting to the proverbial "win-win" situation requires getting everyone on the same team.
Negotiations become difficult (or even impossible) when one or both parties view the negotiation as a conflict between two positions, where the person who abandons his position is the "loser" and the person who sticks to his position is the "winner."
This is especially true in sales negotiations where a customer may be afraid of experiencing buyer's remorse if they don't bargain you down to an absurdly low price.
However, it's surprisingly easy to avoid this situation, according to Bob Nicols, author of 'The Journey to Sales Transformation." Rather than let the positions harden, strip them from emotional attachments by making the issue objective rather than subjective.
To do this, you say something like: "Let's put that issue on the table and see if, between the two of us, we can't figure out a creative way to get what we both want."
This way of thinking puts both parties on the same "team" working on the same problem, rather than adversaries working against each other.