Remember their first name. Ask permission to use it. Share your own.
Use their’s frequently when talking to them. Greet them with it when they walk in the door. Let everyone else in the shop know that you know your customers.
But don’t be fake. If you ask about their daughter and her gymnastics, then care about their daughter and gymnastics.
Sales is a people business. Those who look at the numbers are destined to deliver only numbers – but those that know the people will deliver customers.