This is the sketch I started with.
Next, I took reference, using a two model, a lighting studio, and proper equipment (it was my first time using the studio and equipment - it was great!). Using my photos, I made the drawing, which I then copied to a small size and worked on this value study - a mix of pencil and photoshop.
I hope to have the color comp underway - maybe finished?! - this weekend. And I'll shoot reference for another piece on Tuesday.
Only a few more weeks until these are all wrapped up - yikes! Wish me luck, pleeeaaasse!