Given that I would only have a significantly limited amount of resources, the steps that I would take to increase profits in order to grow my business would be to first look at the situation, look at the scheduling of employees, and look at what kind of food is being served.
The reason that I mention the scheduling is because if there are not enough employees on staff to make sure, the customers are waited on properly and in a timely manner then this would be part of the problem why the wait time has increased. I know that the business was shorthanded anyway but if this were the first problem, then hiring some more employees would be the first step. The next problem was what kind of food was being served if I went with some already made sandwiches and other finger foods this would help the kitchen staff out in getting the food out of the kitchen quicker. In addition, to the already made foods I can have the kitchen staff assign one member to start as a prep person to have some of the food already assembled