Everyone loves a good story, from scary tales told around crackling campfires to the ear-splitting action of a summer blockbuster. Why not put that universal need for narrative to good use the next time you’re pitching to prospective clients? Product samples and a winning personality will only get you so far. To really demonstrate the proof of your pudding, you need a handful of strong case studies at the ready.

“Show them a character they can identify with that’s a happy customer. If your new customer sees himself in your case study, you’ve already won the deal,” says Joe Longtin, regional sales manager for AnaJet (asi/16000), a maker of direct-to-garment printers. He says the customers you want to keep want more than just a low price and product. “They want timeliness, accuracy, good quality and good customer service,” he adds. “That’s what your case studies can communicate.”

The key to a good case study comes before you put pen to paper. “You don’t have to have great writing skills, but you need to have good question-asking skills,” Longtin says.

Put together a standard list of questions for your marketing team to ask satisfied customers, and plan to invest several hours putting the study together – from the interview process to the final draft. Also remember, not every customer you talk to will have a strong enough story to warrant a full-length case study; if that’s the case, pull out a quote or two for a brief testimonial or request a shout-out on social media.

Good case studies contain the following elements:

The challenge. Spend some time drawing out the reasons a customer was looking for a new distributor or decorator. What challenges was he or she facing? What pain points led the customer to choose you? Include details about your customer’s background and the industry he or she represents.

The solution. Explain in detail the promotional campaign or apparel program you developed. What steps did you take to meet your customer’s specific needs?

The results. Describe how the campaign paid off, using concrete numbers if possible. Did the promotion work as planned, bringing in more customers or generating more sales? “Too many case studies are fluffy and do not tell a reader or prospect much at all,” says Valerie Jennings, CEO of Jennings Social Media Marketing. “The results should be very clear and concise and may be the most important part of the story.”

Pictures. Make sure your case study includes photos of the campaign you developed. “Photos are essential,” Longtin says. “We always strive to have proof. That comes in pictures.”

Post finished case studies on your website and link to them from social media. Don’t forget to link back to your customers’ websites. They’ll appreciate the bump in Web traffic and will be more inclined to be advocates and advisers in the future.

Your website isn’t the only place to deploy case studies. “Throwing them up on a website and calling it a day means you’re missing out on a multitude of opportunities to drive additional value,” says Molly Wilson, CEO and founder of PR firm Kickstand Communications. She suggests incorporating case studies into slideshows for sales presentations, or making them a part of press releases or media kits. Other possibilities include distribution at trade shows or inclusion in the company newsletter.

It’s a good idea to have four or five strong case studies at any given time. Longtin uses two litmus tests to determine how long a given case study remains viable: Are you still trying to position those same products? And, is the customer still willing to be a reference? If the answers are yes, then the case study is still valid, even if it’s a decade old, he says. But don’t rest on your laurels. “It’s important to keep trying to refresh them,” Longtin says.