Okay, so a critique.
They're fairly good... but for the first one you need more depth. The picture is rather shallow.
The second one is good as well, but the cheeks on the girl seem a little fat considering she's skinny.
The eye is very nice, but it lacks the striations a normal eye does, and its extremely shiney.
The next one... well I think the nose and mouth should be better defined. Not sure if its a girl or a cat, or a mix the way its drawn. And the eyes are enormous.
The next one... those eyes frankly scare me. They're far too large for one, and all I can see is an iris with hardly any pupil. The positioning of the body is good though.
The sports girl is good, except again, the eyes are large and remind me of the term "blonde bimbo." Empty looking, in other words. And they don't match... the left eye is shorter than the right eye by a good amount.
The girl on the graph paper is nice, but the eyes are too large, even for anime style, which I think is the effect you're going for. Its also off because the positioning of the eyes for the cheekbones, which are rather sharp. Arms are far to straight for being behind her back, they should be bent at least slightly, and the nose and mouth need repositioning and better definition.
Okay, you asked for a critique... here's a small one for each picture. Overall, they're good. Keep practicing tho!