The term 'consultative selling' first appeared in the 1970s book Consultative Selling by Mack Hanan. It describes a selling technique in which the salesperson acts as an expert consultant for his prospect, asking questions to determine the prospect's needs and then using that information to select the best product or service for those needs... ideally, the salesperson's own.
Consultative selling frequently works hand-in-hand with value-added selling, in which a salesperson presents customer-specific benefits related to their product or service. The consultative approach, when properly executed, yields a quantity of information about the prospect's wants and needs – which makes it easy for the salesperson to take the next step and present the perfect benefits for those wants and needs.
Thoroughly qualifying prospects before setting up an appointment is critically important to a consultative approach. If you the salesperson don't know ahead of time that your product will be a good fit for the prospect, you'll end up wasting a long appointment drawing out the prospect only to discover at the end that you can't provide what they need.