Shading comes to mind foremost to me. I took your still life pic and photoshopped in a little shading on a new layer and rendered a light source from the upper left. Maybe you could add a bump map to your floor tile surface for a little extra depth, umm, you can also use the text to cover any blank or dead spots in the picture. Maybe add curtains or shutters on the window frame to dress it up a bit. I know your pain in dealing with clients. I often will get free reign on a project until I show them something, then they suddenly become graphic designers with all sorts of suggestions for improvement. Keep at it though, I think you can turn this into something you'll like.