Given the economic climate I would suggest the following:
Have a staff meeting and discuss how the recession is affecting the business, profits, amount of customers, that kind of thing. Even if you aren't feeling the pressures of it yet... make out that you are. That way if you need to make someone redundant, they have all been forewarned that things are not going that well and thus cutbacks may be needed.
Ask staff for their views on how they feel the service to customers can be improved. Ask them what problems they feel exist and what small changes could be made to improve things. Getting your staff participating in making changes can be a good way of making them feel more a part of the business - rather than just a member of staff.
Evaluate how many staff you actually need to run each shift. Evaluate which staff are good and which need improvement. Discuss individually with staff about how they can improve their performance - thus give them a chance to show improvement.
Do you have a head waitress/waiter type person for each shift? Is giving one of your better staff a defined junior management role a possibility - could that help... could they then micromanage the team?
Are there other jobs that some of the staff may be suited to... is changing job role an option? Or splitting roles - so that for part of a shift someone is serving customers and for another part of the shift they are helping in the kitchen.
Customer Ownership - given your shift patterns and turnover of customers, is it possible to assign ownership of a customer to a particular employee? For example, a customer comes in and the first available employee welcomes them, gets them seated, talks them though Today's Specials (always get staff to try to up-sell customers to the things you want them to buy - but do so in a nice way, not pushy) and menu items (emphasising local produce). The employee makes an effort to welcome the children and give them the pictorial children's menu. Take the order and get the drinks sorted pronto. The employee then keeps an eye on the customers (from a distance) making sure their every need is met - a child spills a drink, the employee is immediately there with wipes and a drink top-up (if you give a free drink, or top-up existing drink in such circumstances). The same employee brings them the food and continues to look after their customer.
At the end of each shift try to have a quick chat with regards to what went great, what could be improved, and a certificate or something for the best employee of the shift (ie the one who made the most improvement, the most profit, what ever criteria you like).