Visiting a restaurant is like a mini-vacation; you’re waited on hand and foot, and you expect to have an enjoyable, stress-free experience.
If you want to delight guests and keep them coming back again and again, it’s important to pay attention to the little things that can make a big difference during this vacation.

Increase the Friendliness of Your Staff
If you aren’t concentrating on customer service and providing ongoing training to your entire staff, it’s time to make this a priority. You’ll make your customers happier when your staff is extra-friendly and willing to go the extra mile. Friendly staff is happy staff. They are employees who are satisfied with their jobs and content in their work environment. Happy, well-trained staff translates to happy customers.

Reward Your Customers
Earn loyal customers with a customer loyalty program. You’ll make your customers happier when you give them something back. A loyalty program is a great way to encourage repeat business and word of mouth referrals.

Turn a Bad Experience Around
Customer disputes are bad for business when they aren’t handled quickly and efficiently. When your diners have problems, they’ll leave happier if you solved their problem with an acceptable solution. Make sure your staff is trained how to handle customer disputes. If someone at one of their tables has a problem such as slow-to-arrive food, undercooked meat or a cold steak, wait staff should handle the problem quickly and efficiently.
For example, we had been out for a dinner with a few friends at a famous restaurant. We were 10 of us, and were having a great time. One of us ordered for the Chicken Salad and were not very happy about how it tasted, so half of the dish was untouched. The server noticed the behaviour and asked us if he could change it for us or give us an alternative. This made sure we visit the place again for its service. Sometimes, unspoken words matter the most. 

Make sure staff knows dietary options. 
Your staff must know the menu and they must know what is vegan and gluten-free without having to “check with the kitchen.” It bothers a customer, if the staff is not pre aware about the available options for all kinds.