For food to sell it has to look appetizing and it has to look fresh. Hot food has to be hot, and refrigerated good must feel cold to the touch.
Food must also look attractive to the audience. Serving an entire salmon is not going to be attractive to kindergartners.
presentation is a feast for the eyes
Food is all about the senses. Sight and smell come first, followed by touch and taste, not necessarily in that order. Sound has an effect too, although perhaps less. Your food service display hits the first element sight, followed quickly by smell.
is the occasion?
How you display lunch in a corporate meeting where people are going to grab a sandwich and go back to work is different to serving food where the experience of the meal is a part of the event like a wedding.
You’re right this is not about real-estate, but in some ways it is. A cafeteria is going to display thing in a different way from the corner store. A breakfast smorgasbord in a hotel will be different from dinner in the same restaurant.
People need plates and utensils first. Put the drinks well away from the food. That’s too much to carry, put things that go together, together. If there’s a sauce for the meat put the close by and make it obvious. The last thing you want is people wandering up and down.
it clean and don’t forget a trash can
Food is attractive when it is presented well but loses appeal when it is messy. Keep the food stations clean and tidy. Put out plenty of trash cans – if only because it will help in the cleaning up.