Do you remember learning the “Scientific Method” back in High School? The process is easy: make an observation, take a guess, test that guess, analyze what happened, and then repeat until the analysis shows the guess was correct. The more background data you have, the better the guesses, but you can learn this as you repeat. The process of negotiation is very similar; you start with the knowledge of what you want but can only guess at exactly what the other party(s) in the deal may want. Therefore, there is a, potentially long, series of probes and questions to determine the background data and come to an agreement on the things you will get and what they will get.
A negotiation is testing and reevaluating the value of a relationship. As an example, let’s look at negotiating a salary for a job. First, is the knowledge that you need a job and have done the investigation to determine that the position is one that would benefit you. On the other side of the negotiation table is a person who knows they need someone to do the job and they have done the investigation to determine that you could fill that need. Now comes the part where the two of you have to agree on the value of the relationship: you want the job to pay as much as you can possibly get, and they want to fill the job at the lowest cost. There may be background of the bare minimum you can survive with, the market for similar jobs, and the estimated value you can bring to the position. You may have other reasons to bargain into the value as well: title, office arrangements, vacation, benefits, etc. These may be items which both sides can use to change the perceived value of the position. These are all background data which enables a better guess as to the terms of the relationship, and will aid you in any negotiation.