I'm guessing that you took advantage of the stencil tools and paint symmetry option features of Art Rage to create this image?
On second thought after viewing another thread you have here, this is from a coloring book? If so you might get this type of tile design effect by using stencils and symmetry option.
The painted colors look good, I would personally use black as the background color (or more correctly, lack of color) to accentuate the design patterns.