Prepare for every negotiation... 1) Focus on Outcomes. What is it that you want to walk away with? Being as specific as possible also increases the likelihood of negotiation success. 2) Support your desired outcome with data that points to its reasonableness. 3) Writing down your key points in advance - and practicing them - enables you to stay focused on what's most important and avoid going off on tangents. 4) Err on the side of asking for more, rather than less [of what you really want]. 5) Be willing to walk away.
