Think about what you liked about your favorite teacher from grade school, high school or college. I can pretty well guess what you liked: The good teacher cares and shows that fact by connecting with you--especially with the eyes. I went to a doctor recently and noted that, during the time he was with me, he only looked at me three times. The rest of the time his eyes were locked onto his computer screen. A good teacher connects with the students with eye contact. A good salesman does the same.
Another thing that identifies a good teacher is knowledge of the subject. A student can tell immediately whether a teacher knows what he's talking about. Product knowledge is critical to good sales.
Good teachers ask questions to make sure the students understand what they're taught. A couple of thousand years ago, a Greek philosopher name Socrates, developed a method of teaching we now call the Socratic method. It involves using questions and answers to arrive at an understanding. Good teachers use this method to help students understand a subject. Good salespeople should use the same approach. Don't come into the sales situation with an answer--come in with questions and let the customer arrive at the solution.
Remember how, as you were growing up, you said to yourself that when you're a parent, you won't do this or that that your parents did and you didn't like.
Think that way as a salesperson. What do you like about that car salesperson you deal with; what don't you like. Learn from watching and observing.
Stop being a salesperson, and become a good teacher; stop selling and start observing; stop talking and listen.