How do I improve my drawings?

How do I improve my drawings? I am learning by myself with no teacher. In the past, I found this website, and I found it useful! But my drawings, which follow the tutorial, look a bit strange. Maybe I could modify something to make them smoother?

https://imgur.com/a/SC8Tk7i

These are actually really good drawings, if not traced. You didnt post a link to the tutorial so i cannot compare but i do think you could focus on drawing more feet, hands and faces as those seem to look a bit off in the drawings. Continuing to practice and really looking at the differences between your drawing and your reference will help you find the small details/mistakes you missed.
I really like the shading you did on some of the figures, it really brings out their volume.

Thank you very much. The tutorial is the book Force by Michael D. Mattesi. When I draw the head and hands, the photo is too small. It's true that I didn't pay attention to those difficult parts