You should know more about the customer than anyone else. Salespeople generally balk at this rule. They say they don't have time to research prospective customers because they need to be out making sales calls. Yet unmatched customer knowledge going into the call is the single most powerful sales tool there is. When your knowledge of your customer's business runs deep, it puts you in the best position to help that customer solve problems and innovate solutions. That is the value of knowledge.