The ability to see from the other party's perspective is perhaps the most important skill a skilled negotiator should have. You really have to think beyond yourself and put yourself into the other party's shoes. Think from his perspective. What does he want? What are his underlying interests?

This is easier said than done. Identifying the other party's interest is also probably the hardest thing to accomplish in a negotiation. Failing to disclose his interests is one of the cardinal sins in negotiation.

How do you discover interests?

Put yourself into the other party's shoes. Analyze and inspect his stance. These are a few examples:

If you are negotiating with your boss for a promotion,

"Why does he not want to promote me?"

If you are negotiating with your husband on the venue of your dinner,

"Why does he not want this restaurant?"

If you are negotiating with your kids to study an extra hour,

"Why does he not want to study?"

If you are negotiating with your business partner on a deal,

"Why does he not want his concession?"

If you are negotiating with your landlord,

"Why does he want to increase the rent?"

Keep asking why. This will put you in his position and see from their perspectives. You will immediately have a clearer picture of their underlying interests. Try role-playing in your head or get a friend to help you with this. Imagine that you are the person you are negotiating with and negotiate against yourself. This is a very useful process in the preparation stage.

When you are in the actual negotiation, you should still ask him why he takes this specific position. Never assume! Asking him why will ensure that you did not make any wrong assumption of his interests in the preparation stage. Be very clear that you are asking him because you wish to find out more about his interests. And be really tactful when you ask why. Sometimes, it can come across as intrusive and even offensive.