Hi there and welcome, Kirke. (As always good ol' reliable Tombow has done the brunt of the welcoming work.)
I hope you don't mind that I say this- your work reminds me eerily of my own, in style and skill, about two years ago. (Something like my older gallery or what I have in scraps at DA)
I believe- Well, I know I have improved since then, so I'd like to share some of the things that have helped me to get better.
The proportions are more or less measured out, but the bodies and poses are composed rather awkwardly, and some of the anatomy seems to be put together as such that it doesn't seem quite right. What's mostly needed to combat this is plain and simple practice, but not only with the drawing portion; with the envisioning, planning and truly-seeing part of it as well. I'd reccomend studying the human skeleton, and musculature, and keeping those things in mind, even while drawing anime style with circles and guidlines to compose the base. Also, study people. You don't necessarily have to take a figure-drawing class; just watch and observe people and their bodies and faces. The contours, the way the muscles form when they're flexed a certain way, the unique shapes and shadows of the face. All of these things can help you even with anime style. (My general idea on doing anime style, barring ultra-chibi-huge-eyed-cartoons, is that you're basing your image on an ultra simplified realism, with a few modifications to shape and size in spots. Paying attention to the way the features of the face look from different angles is one important thing. Another is making notice of the way shadows fall on the body, particularly the face, and simplifying the shading into 'cels', in order to render the shadows and shapes of an anime styled face. Imitating other anime images can't take you very far unless you've developed an understanding of the theoretically 3-dimensional features involved and applied a knowledge of shape, space and light to them. Look at some model photos, pose in a mirror, or get someone to pose for you, and just slowly build up a stronger innate sense of the human body's ever-complex details.
As for your hand picture; realism requres a different kind of shading and mental guidance. You can use various techniques for shading, and you should certainly outline your images, but remember that lines are only for outlining. If you want to acheive something closer to realism, remember that there are no lines outlining our bodies when we look at them. They're very complex shapes, being hit by light and shadow, and should be rendered as such with shading, not outlines. Lines are for cartoons. Shading differences and negative space emphasize the ends of things when you're going for realism.
I hope I was helpful. I know you didn't ask for advice but... XD My inner artist was calling for it.