Attempt at the "grid method."
I must say it was rather inconvenient at first, but after some getting used to, it began working quite well with me.
Most large regions are roughly finished but they definitely still need a considerable amount of detailed work, especially the lips.
I actually have worked more on this than shown here and I am aware that the lips have very little highlights and detail.

I apologize for the horrible lighting and the lack of picture-taking abilities. :[