You've captured the proportions quite well so good job there, my one tip would be to use a wider range of pencil grades to add tonal depth. It looks like you used a HB pencil for the most part, try using a 2B for the darker shading as-well as defining the lines connected to the darker areas (not being hit by light), this will make the drawing stand out more on the page.
All the best!
I'll take the advice thanks for your comment ;)