On top of what Vic mentioned, in the dark enviro, there seems to be a lot of black assets. Make sure your texturing typically falls between values of .3 to .7, it'll make it easier to light.
I am structuring a new approach to the 3D side of a BTEC Level 3 Games course. I would love to hear from the community: hobbyists, students, those in industry, other lecturers and so forth, as to what they believe is the best method to learning 3D from scratch in a classroom - or their experiences in doing so.