Your biggest problem when it comes to poses like these is cohesiveness. Instead of paying attention to everything as a whole, you seem to focus more on the details. Because of this, you lose the flow of the pose. Your poses become stiff, and different parts of the body don't match each other in terms of movement. At the moment, you drew her as if her torso and shoulders are relaxed. Except the problem is that, in that pose and according to the reference you sent me, her shoulder is raised and she's also leaning backwards. Also, because her leg is outstretched, she would also be outstretching her body. It would be extremely uncomfortable otherwise.
My whole problem with the reference you're using is that the clothes prevent you from seeing a lot of stuff, and that really distorts your view. So I'm hoping this redline helps a lot more
Here are the problems. In the spoiler below are all of the pictures. I'll add short descriptions under each so you can tell what's going on:
1. Again, her body is quite stiff and doesn't match the flow of the pose. This can be observed in the followings pics at the bottom of the post.
2. You drew her vagina way too low, and the lines are also too prominent, which wouldn't be that visible when her legs are outstretched (hopefully this makes sense in the pictures)
3. Her breasts look too relaxed, when in actuality she's supposed to be leaning back. Also, because one arm is raised, one breast raises with that arm. Now remember, when fixing the breasts, think of the breasts and torso as a whole. I like to think of the breasts as if they're on an axis that is attached to a cube (which is the torso)
4. The neck would not be as visible in this pose!!! Her shoulders are raised and her head is looking down
5. You already mentioned in the PM that you drew her leaning too forward, and that is correct
6. The knee on the leg bending would not be that prominent. Remember that the reference is of a doll, and dolls typically have prominent knees so...realistically, thats what the bent leg would look like (because we put leg muscles and fat into consideration. Also the knee bone doesn't jut out when bending. It points down)
7. The same leg also needs to be forshortened more
8. As for the outstretched leg, it needs to be outstretched more. BUT!!! as you do this, you need to pay attention to the hips in relation to the leg! This is where that whole "looking at the big picture" thing comes in. You need to make sure everything flows together.
9. The foreshortened arm needs to be raised higher and the hand needs to be larger. Remember, the closer the object the bigger it is.
anyone who wants to look at these, these pictures are NSFW. nudity and stuff
My redline overlayed on your drawing. This way it's much easier to see what I'm talking about.
Without your picture. I'm sorry about the hand, I just kind of scribbled it in.
With a bra, just in case
And without boobs so you can see the torso a lot better
alternative approach to the skeleton, focusing more on the figure and flow