When deciding on a patio design, the first things you have to take into account are the basic structural elements such as flooring, walls, and roof. You may have to choose between wooden or concrete floors. You have to decide whether to use wood or metal for the roof structure, or maybe whether to have a roof at all. You can add some kind of wall, or maybe not. These are all things to think about.
However you decide to go about the construction part, your patio design will ultimately be expressed not by the floors or roof, but by the pieces of furniture and other decorations that you choose to put in the area.