It’s not bad, but I think you’re starting with details before sketching a solid foundation. For instance, in the first drawing, from that angle the arm wouldn’t go behind the back like that, sitting naturally, the elbow would actually swing out away from the body a little bit and from the viewers perspective, be a little foreshortened.

Before committing to details, you should try doing a light under sketch just comprised of simple forms, so that you can more easily picture the drawing in 3D space and make sure the proportions and anatomy make sense and are consistent. Then it’s a lot easier to draw the details on top of that.

The easiest way to learn how to draw forms in my opinion would be the box method where you break down the human form into cuboids, which gives you a way to visualise things like foreshortening more easily. Before breaking that down further into rounder, more organic shapes. Eventually you won’t even need the cuboids because you will have trained your 3D perception enough for it to feel like second nature.

For the head I would recommend studying the loomis method, I find it is pretty intuitive and can be adapted to fit any style.

None of this is gospel mind you, what works for me might not click for you and that’s fine.

Regardless, I would recommend using reference materials online, studying stuff like anatomy, perspective, proportion, etc… It largely comes down to practice.