Foods that you can specialize in.
I wanted to open a bakery when I was young and I did, specializing in things I made well. Along the way I learned new things. If your menu doesn't change from time to time as in offering new things, your customers will grow bored of it and business will go down.
You also need to consider the demands of foods in your area and who your target will be. It'd be kinda strange to offer something like chicken shawarma if you have a very low Arab population because you'd sell little of it. Me, I live an area that has a large Arab & Indian populations so I learned to make desserts from the middle east and India and also learned some soups & sandwiches too and those in my bakery are very popular.
I started small with cakes, cookies, cupcakes, breads. Then went on to candies and eventually soups & sandwiches so I could create more revenue from lunch.
Take a lot of marketing classes.