What every restaurateur wants is for people to come back to their restaurant again and again and again. They want loyal, regular customers who care about their business, who would be sad if their business was gone. The question is how do you build that loyalty? How do you turn a guest, a first time guest, into someone who comes back a second time and then a third time and a fourth time, maybe celebrates all the special moments of their life in your restaurant?
Well there's a simple adage, which is, people are going to be about as interested in you as you are in them. The obvious thing to do as a restaurateur is to spend time with your guests. Spend time in the dining room. Spend time learning who they are, what they care about, what business they're in. The more you learn about your guests, the more you can provide for them. They may use your restaurant as a place to do business. Well then, it's important for you to understand where they need to sit to do their business, what matters to them as they do business, and then provide it for them. They may use your restaurant as a place to unwind and relax. They may not want a lot of interaction. They just may want to be left alone.
It's important that you provide that for them. Every guest wants something different. Learn who they are. Provide it for them, and build a relationship. Every relationship with a guest is based on trust. They trust that when they come to your restaurant, they're going to have a good time. You have to earn that trust through every interaction that you have with them.
The other thing that you can do is to ask for it. Ask them. Tell them how happy you are they're there. Tell them you'd love for them to come back. Let them know that you will be their advocate the next time they want to come in or they want something special. Be on their side and they'll be on yours.