Hi - Can't see the models really, sorry. Lots more light, as few shadows as possible, F8 (aperture) at least. For the backing use a single sheet (bent up behind the models as you've done). Try grey backing instead of white. Models undercoated black are hard to photograph, try and catch the light so that you can pick out details. Failing that, undercoat white and wash them with something sepia coloured. Looking forward to seeing your next pics. Mike