Finished Cover:

I'm going to show you how to get the red and blue effect around your character. I made this cover in like 5 minutes so ignore the ugliness XD

1) So, open the picture with photoshop, color it and change the size if it's too big. Duplicate your picture two times so in the end you should end up with three pictures. 

2) Now go to Layer > New Fill Layer > Solid Color and pick red (I've picked this type of red: e70404). Do it again but this time pick blue (I've picked this type of blue: 0454d7). Now drag one of the "background copy" layer over the RED color fill.

3) Change the Blending Mode of the two color fill to SCREEN. Then select the Blue Color fill and the background copy you've moved, right click with the mouse and select Merge Layers. Do the same thing with the red color fill and the other background copy.

4) Now change the blending mode of the two layers to DARKEN.Then select the Move Tool (V) and select one color fill. Turn off the visibility of the other color fill. Move the VISIBLE color fill a little bit. Do the same thing with the other color fill.