The trick is that, while I pencil out everything at the same time, I have two different steps with inking. Firstly, I ink over all the characters first, and when the ink is dry, I'll then do the backgrounds. It allows me to get to grips with my environments, and allows me to create the 3D effect that everyone's talking about.
Pretty flattering that people are saying that I can make 2D line work look 3D... It's a nice feeling to know I've accomplished something like that.