Dominance is the varying degree of emphasis in your design elements. When you create dominance in your work you are creating elements that command attention and prevail over other elements. You can’t emphasize everything. When you try to do that, all of your design elements compete for attention and nothing stands out. They’re all yelling at the same time. Everything is louder, but still nothing's heard. Some elements need to dominate others in order for your design to display any sort of visual hierarchy. The more dominant element will have greater visual weight than the elements it dominates. You can curate this visual hierarchy through value, size, direction, color, saturation, texture or space.