I'm not sure how well I can mentor, but I could certainly give you some pointers and tips in improving. Or, at least tell you what I do/did personally to improve. Do you have a specific area that you'd like help on?
O.K, I've spent the last couple of weeks trying another one, took your advice with the eyes, they are much darker this time, and I've tried very hard to avoid hard lines. Took a lot of patience, wasn't sure I had that much in me!