Hi, Kekskuchen
I think you are doing great and I think there is one way to reduce roughness is to use bigger drawing paper, I think you are using a book-size sketchbook which is great for some quick short-hand and on-the-go sketching. But you can get a 9x12 or even a large sketchbook and draw one figure per page. In this way, you can really practice controlling the pen instead of confining yourself in a really small space so that will tend to wrist drawing a lot. One other thing you can do is to use your shoulder and that could help too. Hope this is useful.
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