First of all you will need to think about the type of restaurant you want to open. Primarily, restaurants are grouped into three categories: quick service or fast food, midscale where you will get a good meal for a good price, and upscale with plenty of charm and fancy cuisine. This will also be dependant upon the type of food you want to serve, and the type of customers frequent the area.
One idea is to open an ethnic restaurant such as, Italian, Mexican, French, etc.. You can open an ethnic restaurant in any of the three categories, but before you choose take a look at the demographics of your area. You may want to take a demographic survey so you can get information on:
The ages of the customers that will eat at your restaurant business.
What types of ethnic groups live in the surrounding area.
The occupations and income levels near your restaurant business.
How many people will be interested in the type of food you will be serving.
What are the needs, in terms of services or products, of the people in your area? Will you get enough business in the area you are planning to put your restaurant business?
A competitive analysis...