I just ran accross a worthy summary on what could be the best way to approach negotiations at businessknowhow.com.
I have read similar advice in Getting to Yes! The key here is to know what your alternative to a deal is (what they refer to as BATNA: Best Alternative To A Negotiated Agreement, I guess it sounds better than BATAD or BATD 
). If you know where you stand going in, then you’ll do just fine.
It is also important to be creative and try to expand the playing ground to look for something that benefits both (or all parties), even if you think you stand to benefit most.
