When we start a negotiation, we are filled with hope that by using our  negotiation styles and negotiating techniques we’ll be able to  eventually walk away with a deal. 

However, during every negotiation we  are faced with two possible mistakes we can make. The  first is that we end up walking away from a deal that we should have  agreed to. The other is that we end up agreeing to a deal that we should  never have agreed to. 

How can we avoid making both of these errors?