As soon as you've reviewed the regulations, you can then proceed to decide on the square footage you'll allot to each of your customers. Generally, you will need 18 inches of passage area in between the tables and chairs. But, if you want to accommodate wheelchairs, you need to create 36-inch aisles.
More importantly, consider the needs of your venue. A formal setting requires adequate room for a meal cart to pass for tableside service. A casual or even rowdy setting won't require bussing carts in clearing the tables.