Beautiful painting -- Knightley is a peach.
I'd really love it if you could include more technical details about Photoshop for each step. That is, in addition to the "what" info ("I added some color ..."), please enhance with details about "how" (using which tools, brushes, pens and so on in Photoshop).
Any extra info is greatly appreciated, and would really flesh out your tutorial! Thanks again for all the work,