Before covering the tactics, there are antecedents to negotiating that must be understood.
The first is emotion. The more you are able to keep your emotions out of the negotiations, the more capable you perform. The key is not to get so caught up that you become overwrought.
Secondly, always appear as a reluctant buyer or seller. Perhaps one of the worst mistakes in negotiating is to give away your position when you become anxious, and appear to want what the other party is offering too much. The person who wants the least, gets the most; or better yet, the person who appears as though she wants it the least, gets the most.
Finally, regarding controlling your emotions and appearing as a reluctant buyer or seller, the skilled negotiator possesses "walk away" power. This means you must decide in advance that you are willing to walk away from the negotiation table all together. If you ever feel so caught up emotionally that you are willing to give or take what the other side offers regardless of cost, you are not in a position to effectively negotiate.