Zizka's Sketchbook (Nudity and Vulgarity, NSFW)

[Who]

You might want to consider grabbing great exemplar master pieces of the look or approach you're wanting to achieve and doing studies of them. Then you can use the insight gained in your ongoing work. This is one of the most efficient ways of learning about a specific approach or technique without having to reinvent the wheel yourself, or rely on someone holding your hand every step of the way