Don't mention it, I just use colorbalance and mainly touching it up with yellow and greens.
If I look at the image, I don't see much improvement in the quality of the render itself.

It is a bit grainy and the specular highlights are way to bright.
There is some stairstepping and some angular geometry that is easily solved , I would round out the shape of the body of the helicopter as well making it less straight and bigger then the " head" of he heli
I would get rid of the little harpoons that's sticking out the nose and wings and maybe put small chain guns at the front, or some nice airflow carving or something like that.

Also use DOF to make your image more interesting and believeable

See image for clarification