first of all, a comment on the bars in the windows. right now you have them on even spaces from each other, but IIRC this thing is round so at the sides the bars should be closer to each other then in the middle. note also that you can do the same to the glass railing
I think it best to not add in more then the basic 3 shades (dark, light, normal) but to improve looks, you might want to make the shading a bit less wide (making 1/4th of the width shaded in some way instead of more then half what you have now on some places.) another thing you might want to do is make the shading less pronounced, making the shading look less 'angled'
if you really want to go all the way, you can make the shading fully asymmetrical, showing not only the light from the right but also from top.
I think the hulls where the pods are under are cilindrical too? in that case they should have a light and a dark side
if they are half-round or something, they would look closer to this.