What has alway stood out to me in shops that I return to, is that the enthusiasm for the sport itself is obvious in the successful shops. What I mean to say is if you compare a department store where workers are also paid minimum wage and turn over is like every 30 days, from the moment they greet you ... you feel their sales pressure. You can see in their face they don't want to be there. They have almost a distain for the customer. They don't wear the clothes sold at that store and secretly they wouldn't be caught dead in them either.
Same thing in doctors offices (my day job industry) you come into the lobby and there is an opaque window between you and the staff. All the patients in the lobby are doing nervous twitching things with their legs and hands. Admittedly it's rarely a cause for "fun" to go to the doctors. Being new to the scene you go up and knock on the glass - no response. So you sit down. Five minutes later someone slides the divider open and has this scowl on their face which says "why have you disturbed my slumber? What could you possibly want you small insignificant person?". But what is being forced from their lips is a canned greeting. "Welcome to doctor ... take this clipboard and find your own pen ..." (and what is seen on their face is "here's enough paperwork to last an hour, so go sit on the floor shmuck and quit bothering me.)
In a successful scuba shop the employees are divers themselves. They love diving, they love to talk about diving, they love to talk about diving with you. They are ready with stories to tell about yesterday's dives, or a recently unexplored site, or some humor to brighten your day. They want to help YOU because they love to be around divers. Their face exudes - "I love SCUBA diving, please, please ask me a question about it, or give me a minute to tell you a story".