Customer relationship management, or CRM aims to manage relationship with customers during its lifetime, from the earliest stage, when the customer is not yet a customer but rather a prospect or a shopper, to the end, while he decided to switch service or is not in the target anymore. Hence, CRM should not only take care about customers, but should also focus on the decision making process, and therefore, prospects and shoppers should still be taken into consideration. This is the reason why a lot of CRM programs and softwares are including prospects into their customers' profile, in order to get some data, and be able to provide them the offer tat will trigger the purchase.
In order to provide the best response to prospect, you should leverage the data and knowledge you already know about your own customers. Your customers at some point have been prospects, and identifying why they purchase your product, will enable you to emphasize those aspects.
Also, for ecommerce businesses, you could check the shopper's behavior to identify which aspects turn them down, when they have decided to leave the website and why.
To get further details about prospect relaitonship management, if you speak French, I propose you to check this pdf file, and to visit this blog.