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Hi,
You made the first step and you put your self in the critique zone, you did great.

Let's talk about the piece and your goal:
Rendering ( Use of Shadow and light)
There are a lot of video about rendering, i suggest you Proko, he is realy easy to follow.
Said that let's analyze the piece.
You are using in, that's mean you CAN'T render thing in greyscale but only in Black and White, that's the hard mode, also the ink is punitive medium , if you are studyng grab a pencil ( >2b , an eraser and a smudge )
Focus yourself on understand forms and planes of the head, then you start think about your Light direction, if a plane face the light you are going to put it in light color, if he don't you are going to make it darker, easy as it come.
That's all about the rendering, but as i can see, in this piece there are a lot of mistakes about proportion, design , stroke modulation.
In my opinion you should take it easy, take easy step, leave the rendering of a human face for a later stage ( it's a pretty hard thing to do )
Focus on 3d form, on shapes and on proportion, take your time, don't go for quick drawing, just study.
Keep grinding my friend,
I can't wait to see your improvements.

This looks really good and extremely cool! I love the shading on the neck especially, it really adds a very dynamic look. One thing I would say is use the neck/throat shading on the cheekbones and face as well. It would help the drawing to look more unified in general, and make the shadows look more intentional.

I love the pose of the piece also, and you did a great job conveying curls/wavy hair!