Redline. ;o!
[link]
Blah, it feels so weirdy not using my stupid angles. xD But I wanted to try getting all the curves right for sure, 'stead of just cutting them straight like I usually do.
And I kind of didn't really mess with the head or do hands. I guess I just kind of.. don't feel like doing 'em, neh. x3 Hands would definitely be a pain on a laptop mouse. And I'll just recommend for the head to maybe make it just a little smaller and move it forward and down so it actually sits on her neck. Right now it'd more than half the size of her shoulders if you looked at her head-on, where it should only be about a third of their width, and it's in a really off position.
Anyway. Ohhhyah. There were definitely some mistakes you pretty much inherited from the original. Darn anime anatomy - it's so notorious for being off. xD I tried fixing both those issues and a few others you made on your own - especially how you ended up making her even thinner than she already was.. which was pretty darn thin in the first place. That tends to make the person look really, really unnatural.
A big thing to keep in mind to prevent the look of over-skinniness is that women's hips are wide - even the thin or relatively un-curvy ones. An average female character's hips will almost always be wider than the ribcage.
Oh, and this little guide should be pretty helpful for basic proportions for a girl. ;o I outlined a couple of those kinds of tips in my redline, like the bellybutton thing, but that pretty much gives you most of those little proportion things an artist should know.
Buuuut, best thing I can suggest is referencing from life. ;D Even if it's not full-out studies or sketching every day, it can help a lot. You've got a full body of reference materials right there on you - having issues with hands or a particular pose? Look at your own hand or pull out a mirror. It really helps.
Ohcheese, long post.