Walk in someone else's shoes...

When you approach someone to make a sale, that's the goal you have in mind.  But it's not what the customer is thinking.  The customer may be thinking about personal problems, things they have to do, etc.   The goal a good salesperson has in mind is (1) capturing the prospective customer's attention, and (2) finding out what a product can do for them, then (3) closing the sale by making them want to have it.

To paraphrase something Dr. Phil said in a speech he gave about when he was a consultant on jury selection, but it applies so very much to selling products also:

"If I'm going to sell what she (he) buys, I'd better see through her (his) eyes!"