From the look at your sig area thats not a bad sig for you just work on effect flow its kinda random but in a way its not from the pose of the render. move the white lines to the side in this one i think it would look better. or a black thick border for a movie look.
Simplicity works well on your sig but it lacks a little bit of effect. Just a little bit but the I like the simplicity of the idea. The background also looks nice.
nice job however the building on the far left needs to be either blended lighter or removed completely; it screws up the focus which should be on Thor