Sithlord,
Awesome customs as always...
I've just caught up with your image, thanks for asking for some advice...
If I were to be truthful, you can do much better, you have all of the photoshop skills, you just need to apply then to the image or images.
The image is a work of art, you need to treat it as such. Start thinking about the shadows more, the light source is above and to the right of the figure, yet the figure shows light coming from the opposite side. The guy is in a desert, yet he has a blue, cold tone.
I use tools like colour balance, gaussian blur, I lasso part of the image (using feather) and add or take away light (using Brightness/Contrast) and I use the Spotlight in Lighting Effects to add light source.
I would really love to see more people presenting their customs as works of art, and you SithLord are better then me when it comes to graphics, you should be awesome at this too.