I'm digging out some old work to show you guys some process, since the new multi photo feature is perfect for this! Here's an illustration I did for Tor.com short story 'Tom, Thom' by KM Ferebee.
Scroll through to see the steps:
1. Sketch options sent to the AD
2 Detailed/referenced sketch
3 Pencil drawing
4 Digitally coloured final.