okay, here a little process/walkthrough with some quick notes. Maybe someone finds it helpful:
1: layout sketch, basic colors and shapes. Want a cover-like feeling so I choose an in-your-face approach.
2: start rendering with a hard edged brush and an airbrush put in basic color and light/shades
3.little color adjustment and more quick rendering
4.realise that the pose is too standard, so I change it. Make him also bigger for more impact. Also change the shape of the bg for a better negative space.
5.The time consuming part begins the more detailed rendering.
6.detailing the background
7.change the backlight, put more focus(contrast) on the face, try a different lighting for the background in the lower corners
8.go back to the darker background, more detailing on the bg, add motion blur to the FG (also tried to blur the whole BG(not seen here) was intense but lost a bit the feel for the scene)
9.final rendering, changing little stuff like his headshape and adding stuff as the DD on his chest. Also throw in a second bg color to enhance the depth
Overall I tried to keep it simple enough to keep the flow of it.
final pice: [link]