Don't shade the bottom like that. These are cylindars, so just give these vertical bars of shadows. Speahking of which, you might want to make this thing drop a shadow to give the illusion of depth.
Also, the shading is inconsistent. There are areas that are pillow shaded (EW EW EW) and there are other areas that are some what shaded properly.
Also, the shading is inconsistent. There are areas that are pillow shaded (EW EW EW) and there are other areas that are some what shaded properly.