By now, you’ve likely heard that storytelling is a very effective sales tactic. But, deciding what story to tell can be a challenge, especially for a rep who hasn’t yet used this technique. Entrepreneur contributor Dustin Mathews shares three criteria to use when deciding which stories (or case studies or testimonials) to tell. He believes the criteria help narrow down the stories that are the most coherent and will be the most engaging for audiences.

Prove character. Reveal strength of character through stories that show prospects what it’s like to work with you and your team. Share a story or testimonial that showcases what you personally bring to relationships. “Your case study should include the clients' personal account of the experience, and the character testimony for you or your team they worked with to gain their results,” Mathews explains. “This solidifies you, in the minds of the audience, as being integral to their own desired transformation.”

Provide social proof. Casual reviews, such as those from Yelp, are an excellent source of social proof. While not all reviews will be specific or customized, they will provide a digestible snapshot of your credibility. Essentially, as Mathews points out, you are doing the prospect’s Googling for him or her. By sharing what others are saying about your business, you build trust. Have you received a review from a known industry professional or authority figure? Make sure to include it; you’ll enjoy the transfer of power and influence.

Showcase the speed of results. Prospects need assurance that they will get results in a timely manner. Tell a story that highlights a time when you delivered quickly and efficiently. “Elaborate on how these customers have tremendous momentum right away after starting to work with you and your team,” he suggests.

When crafting your next story, see if you can include these three topics. If not, try telling multiple stories so all three are covered. Note, though, that each story must have some element of third-​party credibility. “Stick to this formula,” Mathews promises, “and your audiences will remember you and your work, based on the stories you shared with them, for years to come.”