I see improvement! Especially in your line confidence! In your earlier stuff, the lines are way more sketchy as you try to find the shape on the figure, but you can plainly see that in your later stuff, meaning you have a far better idea in your mind and in your hand what you are trying to portray.
You seem to not really emphasize the form of the neck very often and forget to toss in the colar bone. Two quick lines on the top of the torso for the collar bone is great for knowing where to position the neck and the arms. It also helps indicate when the person is bent over. You aren't focusing much on the head, perhaps for studying purposes, but practicing the neck a little more helps direct the rest of the pose far more than you'd think.
You're doing great! Im seeing some techniques used that I forgot about so I'll try to remember them for my own studies!