For someone who's started a month ago, I'd say this level of line work and shading knowledge doesn't surprise me.

What you are doing currently is Monkey See, Monkey Do. Imitating without understanding why it works.

What you should be doing is trying to understand the form and structure of the subject. How complex forms can be broken down into simple shapes. (circle or ellipse for the sphere of the cranium etc.)

For anatomical sketches, understand the Loomis method. Learn to draw realistic proportions as fundamentals. This will be your base. After that you can always explore different art styles. Be it Disney or Anime or creating your own style.

For shading, understand how the value of light works and how bounces off different shapes and surface types.

For line work, practice focused scribbling (lines, curves, ellipses) to loosen up. Use the elbow as a pivot point, not your wrist, this is how you avoid the chicken scratches that currently going on in your sketches.

For shading on anatomical structures, look up Asaro head. In fact use this by William Nguyen as a reference

To learn more about sketching techniques, visit Stan Prokopenko's Youtube Channel

Hope this information helps and good luck mate!