aside from the fact that this drawing is kinda scrappy, it's not bad. however, don't forget about bounce light underneath the figure here. the darkest part of the shading on the apple would be where the shadow begins as the main light source fades. then, the reflections from the surface would bounce onto the bottom of the apple. so the further down you go on the shadow, the lighter it actually gets. not by much, but the subtle change will make a big difference.