Keep that coral more alone and make sure to not have it clash with other colors.
Once you have your aquascape done, then what? The rock work needs to have flow and correct composition of color introduced. Coral placement is just as important, if not more important then rock work. You need to throw the viewers eye where you want it. One big thing to remember is you do not want a group of green, a group of red and, a group of blue. You have to pretend you cannot touch the same color together. If you have two red coral then place one of the far left and on on the right. The trick is to throw the color throughout the tank. That is one rule for contrast and composition. One thing also is keep in mind where you want the viewers eye to gravitate. Keep that coral more alone and make sure to not have it clash with other colors. Having a bright red coral, surrounded by blue coral will make that coral pop and draw your eye to it. If you want to get very technical as if you were painting you can look at a color wheel.