This coloring page is full of playful energy! The black cat's fur looks like it's glistening in the sunshine, as it chases its bright blue ball that is bouncing around. To add some contrast to the design, I would choose to color the cat in a warmer shade of black and use a slightly lighter shade of blue for the ball, so that they really stand out. The leaves of the surrounding trees look like they'd be pretty in a lush green color, while the background sky could be filled with a light blue, to create an airy atmosphere. The cat is the real focus, though, so be sure to really bring it to life with some bold colors!