To help with that, I like to start with using a lighter pencil and drawing the entire outline of the object, or draw the outline of major parts (Head and Body, Forearm and Hand). That way, I'll know if it fits before I start making bold confident lines.

There's a good illusion of three-dimensionality. I think you can further push this by bringing in a clear scale of 5 values, as right now I can only really see 3 distinct value steps. It seems like the reference has more values in the shadow than the light (though it may be in part due to the camera, so cross reference with your first-hand observation) so a good breakup would be two values for the light--one for the main area of light and another for the brightest highlight--and three for the shadow side. You're definitely on the right track though, so you got this!