Seems like you got a good start, but you seem hesitant to go truly dark with your shading. I had the same issue when I started. You need to utilize the full range of shading to make things truly pop. I have wrist issues so getting very dark shading with graphite is hard for me, but try more with charcoal and charcoal pencils. You can even try covering an entire page lightly with the broadside of a charcoal stick then use an eraser to lighten the highlights, darkening more as needed with charcoal pencils.