Dealmaking in Negotiation: Six Strategies for Creating Value 

Here is a link to the Harvard Law School's Negotiations Daily Blog - Everyone can learn some strategies for haggling in negotiations.

This blog is a great resource for everyone, but especially if you are buying or selling real estate. It includes business negotiation scenarios.

Daily they post interesting scenarios on real life and world negotiations and what techniques, skills and factors were used and the success of each. 

You learn BATNA - BATNA is a term coined by Roger Fisher and William Ury in their 1981 bestseller, Getting to Yes: Negotiating Without Giving In. It stands for "Best ALTERNATIVE TO a negotiated agreement."

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