Word of mouth is one of the most useful advertising tools that you can take advantage of. If you keep your prices reasonable and the food is good, people will tell their friends to eat at your restaurant.
Try to find a market that is not already over saturated. If there are, for example, ten burger restaurants, and only one or two steakhouses within your town, then you probably will not want to create another burger joint. There would be too much competition already.
Do not over advertise in one specific place. If people see the same advertisements over and over, they tend to lose their meaning, and you may even begin to annoy your target audience.