You're not alone! Many people tell us they are fearful of negotiating. Most are afraid they don't know what data is needed. Or they have attended a negotiation workshop that provided them with hundreds of tactics, but are afraid they won't recall what they are.
When you know the facts, including what are the other side's alternatives to not choosing you, we see the person relax. If you have created options for your customer that fit their needs, and is marginally better than their alternatives, bringing these facts to the table and not getting pulled into the emotions, makes all the difference in the world.
Listen to Brian Dietmeyer talk about this in this short video.