You need to brush up on anatomy and proportion.
Quite a few aspects of the most recent picture looked better in the first, but I will go off the second, assuming that's what you're working with.
The feet are entirely too small. They're generally about the length of the forearm (excluding hand), or about two thirds to three fourths the length of the calf (excluding knee and foot). The far one looks decent, probably a little too rounded and the toes might be too short. Given that there are drastic variations in toe size and shape I'd actually not worry about that one too much if I were you, unless you want her to have an overall slimmer foot.
The close one is very odd. The angle seems like it would be very uncomfortable. It would be more natural if it were facing away from us.
I would say, you probably have two feet on your body and you can probably see them enough to study and reference them while learning to draw feet. You will have to use outside sources too, since seeing a foot in all natural angles on yourself requires immense flexibility.
The calves are lacking calf shape and the bone in front is bending the wrong direction.
Knees look unnecessarily round and unknee like. Study these from real life if possible, photos will aid too.
Thighs should probably flatten out a little more near the top. It's a fairly fatty area on women and tends to deform whenever pressure is applied from any direction, including when she's lying front down on the ground.
Lines between the buttocks and thighs - at least where you have them - are unnecessary. The butt can still be fairly round but it connects to the thighs differently, more like an obvious separation of flesh rather than one continuous line with another line separating the two.
The hip area in the front is far too defined and round. The squishing out isn't so bad, but the line crossing over the thigh just adds a wrong definition to the whole thing, like the hip is some bizarre rounded thing sticking out of her.
Back is angled wrong, should have a more obvious s shape curve to it. Stomach should be flat against the ground, and the definition for the spine is too close to us.
Judging by how the breast is squished, I'd say it's fairly large. I'd also say from experience that laying on them on any surface that isn't soft as hell hurts. Maybe she's different, I wouldn't know, but it just looks uncomfortable.
Also, because her arm is raised I would suggest that the bulk of the fatty tissue of the breast would also be raised; it's too far down.
Study shoulders and all their deformations in various positions. There are photos everywhere of people with their arms in a bunch of different positions from a bunch of different angles. I realize a lot of people get shoulders wrong (I was royally jacking them up until some lulzy people pointed it out), and it would be very beneficial to study the musculature and how it actually looks on people.
I cannot quite figure out what's going on with the far shoulder.
Elbow seems oddly large and knobby, should be smaller and taper down at angles to meet at a rounded point.
The hand is... messed up I guess. Fingernails are pointing in opposite directions - probably something that would look 'wrong' in any case except where the hand is obviously in your face - and the way the hand is situated would be uncomfortable.
Skeletal structure, musculature, fatty deposits and how the flesh lays are all things you should work on if you intend on creating convincing creatures and characters.
Also, and I leave this last to mention because it's fairly arguable: the tail.
It seems unnecessarily high up, should be situated further down the buttocks, coming out from where the tailbone is.
The angle it's at also seems very uncomfortable, like it's gone and turned to an acute angle against the spine. It should generally remain obtuse. Even in animals with upward facing tails (house cats, dogs with curly tails) there's a smooth transition from the spine to that upward facing portion of the tail.
I may throw a redline over this because I feel I'm being somewhat vague and unhelpful.