Yeah, you're on the right track of adding greater details and textures to your environments, I can't say much about the lighting since I don't know the context or mood, these usually dictate the temperature of the paintings. I can't be too critical since, like you said, it's still incomplete. But as for hallway details, maybe a fire extinguisher, a potted plant, a vacuum cleaner. The bathroom, definitely piss, crude graffiti, water stains and little wear/age on something. These do already look very good and I'm sure you'll able to continue improving.
Wardsmith
I literally cannot give any advice here. Those images are higher quality than anything I've ever drawn.