I've done a contest between sales on who can bring in the most 5 star reviews. They had to have the customer provide the approved email. I would run it for 3 months and have a PowerPoint that I presented to sales that also contains an email they can use to send to customers. It was successful especially when you provide an update every week on where we stand on reviews. It's important to stress to sales how the customers need to do the reviews. It can be frustrating and Gartner claims that when the review is rejected, they let the customer know what they need to fix. However, customers are busy so they should know upfront how to do the review.
