Most restaurants can classify their customers into clearly identifiable groups such as business, special occasion, seduction and casual diners. Start with the most valuable group. Set specific targets for your advertising. Decide whom you want to attract, and when you want them to come. Let's take media first.
Most restaurants have a trading radius of about five kilometres.
This will have an important bearing on the media or vehicle used for advertising. Sure, thousands of people may see you message, but most of them are too far away to be of benefit to you. I usually get an argument at this point. When I go back and examine what they've done, it's the message that's wrong, not the media. An advertisement that is presented in isolation is generally better than an advertisement that is part of a barrage of other messages.