The three core elements of a successful restaurant are food, service, and ambiance. Food is the most important element because it is what draws people in and keeps them coming back. The menu must be appealing and offer a variety of options to appeal to a wide range of customers. Service must be friendly and efficient in order to keep customers happy and ensure they have a good experience. Ambiance is also important as it sets the tone for the restaurant and can help create an inviting atmosphere.