The ‘Third-Party Selling’ technique
If you've done your homework, you can bring specific examples to your sales calls. Whether you are a brand new salesperson, or a 20-year veteran working with a brand new prospect, a proven way to establish credibility is to reference success with other clients.
Source: Sales strategist Kelly Riggs
"Third-party selling" is the process of strategically describing the successful implementation of your product/service with other customers in similar situations. When using those "third-party" examples, you need to be specific and detailed. A good story will put your prospect in the shoes of another customer and help them to see the possibilities for your product in their own situation. It will also subliminally communicate your competence and your credentials, eliminating some of the psychological barriers to making a purchasing decision in your favor.
Past success builds credibility.