Visual Unity
Visual Unity deals with the visual elements like colors, images, textures, etc. These elements should be placed in a way that they enhance the information present on the interface rather than drawing attention towards themselves (if they are not supposed to). Colors should be picked and used in a way that they promote the main content of the interface and not go against it. They should be picked thorough a color scheme so that they can harmonize with each other and not look to bland. Textures should be used in a way that they enhance the look of the interface and not look out of the place. These visual elements should complement each other well.