~FergiGirl~
The Titanium Spork
Study anatomy and proportion.
Loads of lifedrawing.
Study light and shadow.
Then move up to perspective.
Then composition and color theory.
Maybe you could be a bit more specific?
You pretty much gave a very brief description of a typical art class without giving any examples.
How do you expect her to get better if you don't show what she's doing wrong?
Like here http://kokoloveshercookies.deviantart.com/art/Gaia-Avatar-133266269 koko, you got the general layout of the girl right, though the legs look a little large, and the left arm has a bit of a "macaroni noodle" look to it without a clear elbow.
This http://kokoloveshercookies.deviantart.com/art/Link-and-the-Magical-Cookie-133262433 is simply adorable
heart though I'm more of a Ganon fan myself XD
I notice alot of new artists like the chibi style, it can be very useful for learning basic proportions, as long as you keep challenging yourself and don't do just chibis
I understand where you're coming from, but, in the long run, more specific advice is only useful if she makes the same (or similar) mistakes consistently, which she doesn't.
There are a whole bunch of good tutorials on each topic linked to in the guild stickies, so I don't need to go and mention tutorials, either.
At the original poster: really, what you need to focus on is drawing from life. Set up still lifes and sketch them. Go to a coffee shop and draw people (sounds stalkerish, but usually, they're flattered). Go to the beach and draw people sunbathing. Go to the park, and start drawing people walking by. When you really improve, draw a little kid on a swing, and try to show the motion.
Above all: draw realistically. Not all the time, heavens no, I wouldn't force that on anyone, but you need to learn how to draw realistically before you can go back to stylizing, because if you try to make your own style from something already stylized (in this case, manga), you're going to make it really warped, and not properly representational. If you learn to draw from life, then you can take that and stylize it, and it'll still look good.