The Staff In This Restaurant Making You Feel Welcome

A good tip is to listen to customer feedback & criticism and offer to compensate the customer with a complimentary dish or voucher as an apologetic gesture. This will make the customer feel heard and important and increase their chance of returning to your restaurant in spite of a negative experience.  It's also important to gather as much feedback as possible and respond adequately. Consider setting up an automated post-dining survey to gather feedback from as many diners as possible, analyze the data on a daily basis, and take actionable decisions accordingly.