Three important things regarding business negotiations are, 1st is Toughness, 2nd is Fairness and 3rd is NANIWABUSHI (Concessions).
You should have the awareness and responsibility that you are negotiating for the company and Toughness is important for the negotiation. If you don't have Toughness, the other party will treat you lightly and you will be forced to accept adverse conditions. Even if you could negotiate with Toughness, you will lose your trust if you negotiate in unfair way. By doing the negotiations in the spirit of fair play, you will be able to obtain the trust of the other party.
Even if you could earn favorable terms to your company after tough and fair negotiation, it is not enough. Finally, it is important to cede one step to the other party. Only one side wins are not good in order to make better long-term business relationship after contract established. This is the Win-Win negotiation.
When I was engaged in big deal negotiations as chief negotiator, I was tenaciously negotiated strategically while simulating thoroughly the other party’s information. I was concentrating on finding the real intention of the other party in hardball every negotiation.
At the end of the long-term severe negotiations, I pointed out that the other party's remarks were differing from previous remarks. Then the other party finally gave up and reached self-defeated (Shoot himself in the foot).
After the close of negotiation, there was a phone call from the other party and he said that you were all correct and he was completely defeated with this negotiation but he requested me a little more money because he has wife and children to feed. And then I immediately accepted his request.