You're good at copying pictures. I'm not fond of Ben Krefta books though. Did you know Ben Krefta joined DA? I think his user name is Bunt or something. Can't remember. His books never helped me to draw. I had to go all the way to China to get some books and it wasn't a waste of time I can tell you!
Excellent color job, here! (I have that book!) It's okay to use the book, just make sure you're able to use what you learn from it on drawings without references later. Still, you've got quite a knack for transferring what you see onto paper! I see nothing wrong with the proportions or placement, and the wrinkles are perfect! You sure you didn't have more that just "some help"?
Aww. Personally I can't hardly tell any differences in the drawing except that it's flipped from how it's printed in the book I have. (Obviously the color scheme is different. That was very well done! I meant the outline, if the previous statement was confusing.)
hm.. I have that book to.. well. I would say give her more shine and harder shading... If your goind for anime ish style... more hair tint too. Also - I would suggest Making it more to your own style.. and less of what is In the book. No one really goes places in copying... but I see you tried. :3