Nice work, love the posing and facial expressions and above all the story telling displayed in your pics! Just to be a noodge though, try using the burn tool in your post-work graphics program to create shadow effects on your characters and as well as upon their surroundings and a blur tool to focus your viewers eyes upon what you want them to see by making the other bits of the pic a bit hazy and ill-defined looking like the depth-of-field selector on an old 35mm SLR camera would do. Your 3D rendering engine can do that for you if you 'tell' it how you want it done via the selector dials it allows, but on my cheap rig it really slows down my render times to a crawl. Backgrounds can really 'sell' a pic but they are so hard to make realistic looking that mostly I avoid using them in favor of a plain black 'canvas' - sometimes I'll claim it's my inner Zen manifesting itself but in reality I'm mostly way too lazy to devote the time required to do a background up properly. LOL
Render on Pauline! :-)