Rather than starting from scratch in a raw space and building a restaurant from A to Z, you may want to try to find an existing restaurant that is for sale that you can take over. So the question then is how do you find a restaurant for sale? There are many ways to do that.
One way is to enlist the help of a broker. They are going to want a fee, but they often know which restaurant leases are coming up, coming due, and which ones might be available in the near term. They can be extremely helpful because they also know the potential rent for any restaurant space that you want to take over.
Another way, maybe a little less scientific, is to pick your neighborhood or your area that you're interested in finding a restaurant in, and spend time in it. Notice which restaurants are always empty. I'm afraid it's a pretty simple fact that if a restaurant's never full, it's not doing well. While I'm not suggesting you be an ambulance chaser, it is true that by getting to know a neighborhood and how the businesses are behaving and how the restaurants are performing, you might be able to understand what restaurants will be becoming available in time.
Another thing that you can do is talk to restaurant industry people. Talk to people in the business. Talk to restaurant owners in the area. Develop some relationships. Tell them you're looking for a space, for an existing restaurant to take over. There's a network of people, and they're talking, and you can find the information by becoming a part of that conversation.