I think you didn't work on it enough.
Thinks you have to improve:
-Text ,it looks horrible.
-Do sth with the bg. Dont just google 'lightning' find some picture you like and just leave it as it is.
-The renders dont match with each other.
-Put some effects. I can easily tell this sig consists of 4 layers.
-Clean your renders. I see some letters next to the render on the right.AND behind the left one.
-Follow some tutorials and see if you can do what they say and if you like it.
Generally this is a very weak sig -even for your second- and you have to try experimenting more in photoshop and reading tutorials to get a grip of GFXing.
~with all respect and honesty.
I'm sorry if i sounded mean