Red: Looks like just an erased part of the render. Blending doesn't look right when you do this.
White: I would add some lighting effects here. Even if it's something as simple as a soft white brush.
Yellow/Blue: The yellow is what the effects you used made the flow like. Blue is where I would have gone with the flow based on the render.
The rule of thirds isn't always to be followed, but generally it's a good guide to focal placement. The red circle is where the focal of your sig should be. The green X's are where you want to place the focal on a piece.
tl;dr: No lighting, depth, or flow. Overall a very boring tag.