Set the big blue ripple thing behind sora to screen or lighten or something. If it doesnt look good change it back I have a feeling it will help. Also, the random white lines mess with the flow.
Not every experimentation works out well, but the effort is what counts and that's how you learn. The bluish lines/brushes/whatever they are kind of throw off the sig. Try to make them go in one general direction for flow. The background colors don't blend well with the render so it looks like it's a clutter of random effects. The lighting has a good idea, but since you didn't darken any other part of the sig for realistic lighting, it looks like some random spot of light. You also lack FG effects and that makes the sig all the more monotonous.
the background is bugging me, you might wanna add a C4d to the background, and blend the render in more
Only complaints are the color and the random white lines going everywhere--get rid of them. >: The color could use some work. Add some gradient maps on a layer mode to alter the color. That way the light doesn't look so... white.