step by step
1: create structure with hard brush adn a couple of custom shapes
2: refine a bit in black and white to make volume pop out
3:I took a photo that i blur pixellate in multiply mode
4:I reduce the opacity of the black shape to 50% giving me a 50% grey so i can overlay on it color or texture without loosing the original colors
5:add textures and some photo incrustations
7:tweaks , dodge tool, high pass , sharpen etc...