The answers you have received are good ones. I am just adding, you need to determine your target audience by the food it will be selling and the cost of that food. Who will you cater to? Teens? Adults? Seniors? Who can afford to buy your foods? Will you serve specialty foods like Mexican, Chinese, or will you have a fast food type of business? And, are there any other restaurants in the immediate area that sell what you will sell? Questions along these lines should help you figure it all out.
Good luck on your project!