Keep in mind that a lot of what you are asking about is ARTIST controlled. For example, if you choose a green that is 0,255,0, then it is going to be very bright and saturated. a more "real world" green might be 90,140,90.
On top of that, you will need proper use of things like shadow maps to help light things more realistically than just using the lights. Beyond those things, remember that blitz isn't using any of the new rendering techniques (pixel shaders and such) so you are only going to be able to get so far with a DX7 engine.
On top of that, you will need proper use of things like shadow maps to help light things more realistically than just using the lights. Beyond those things, remember that blitz isn't using any of the new rendering techniques (pixel shaders and such) so you are only going to be able to get so far with a DX7 engine.