Once you've established why your prospect should change what they're doing today, you're ready start proving why your prospect should choose to change with you. However, most messaging on "why you" lives in "Value Parity," or areas where you and your competition are similar. Focusing your message here doesn't create a value proposition. It creates a "me too" proposition.
Instead, you want to focus on what you can do for the prospect that is different from what the competition can do. This is your Value Wedge - where you find your distinct point of view. When you focus on the elements of your solution that are unique to you, important to your customer, and defensible, you're changing the buying criteria in your favor.