Late as always i see... As most people already have pointed out, lighting and textures make the big difference. In this case, i would go for some highres image textures. As for detail work... What i usually do when creating my environments and want to have more detail, is to try copying some of the existing objects, flipping them in all axis, pulling/streching them and see if they get a new cool shape that looks good with the rest of the stuff. Dont worry if they get embedded in an other model. As long as the render looks good, it works. Postwork and color corrections can also make a huge difference, but when it comes to detail, youll get a long way by randomly adding smaller existing models, sticking out here and there. Not sure if these last things were asked for though... :)

Rudolf Herczog
Digital Artist
www.rochr.com