This is good and an interesting style. Maybe you could improve a bit on the shading, especially below your eyebrows you have two distinct planes of shading. Try to not have shading side-by-side, but always a continuos plane of strokes. To darken it, you can then go cross-wise or set more, shorter lines between the already existing. Think of layering the shading, not putting it side-by-side. Shading also looks better if it is not the backnforth-motion with the small loop at the end, but clean strokes with a straight direction. Makes it look more professional in an instant.
Also, try to replace the continuos lines used for limiting edges like the lips, eyes, nose with a very dense, tight shading. It instantly takes your drawing up several levels. On the other hand, the way you used the lines to define your dreads looks very interesting. Play around and find your style with that.

You have the proportions right, the fall of light on your face, you can convey a feeling with your sketch. You're on a great path.