Even though it's at least four years old, this picture still captures something. At the time I was doing a lot of 'darkened room' type pictures, ( Moonlight and Stonework were also from that period.) basically teaching myself to think in terms of negative space rather than positive. Thinking that way doesn't look very different at the sketching stage, but it prepared me to deal with the concept of layers in Photoshop. Plus I can't imagine making my black and white WoW drawings without being about to toggle back and forth between negative space drawing and positive space drawing.
Okay, so what's all this 'negative and positive space' crap about, you ask?
Most simply: are you drawing black lines on white paper, or white lines on black paper?
No, I'm not fucking with you. This is a deep question for an artist. Okay, so most of the time the actual paper or canvas is white anyway, but I'm speaking about conceptualization here. Whether you're dealing in positive or negative space matters an awful lot to the eventual mood and focus of the drawing.
Sure, it gets more complicated when you're talking about color pictures, but there are some obvious examples: Rembrant and Carravagio are mainly dealing in negative space (white on black) while Monet is a pretty strict positive space (black on white) guy.
Most casual draw-ers don't even realize thinking in negative space is an option. This is partially because most of us are as young children given a white piece of paper, a dark marking utensil, and are carefully coached to draw the outlines of an object. (Even 'coloring in the lines' supports this way of thinking, as it's a solid darkish form on a white background, hardly ever is it the background you're 'supposed' to be coloring.) I clearly remember the first time I was expected to deal with negative space in an art class. We were doing batiking, in which you mask part of a bit of cloth with wax, dye it, boil the wax off, and repeat. I got so frustrated I about cried in class, in highschool no less. I blame this partially on the teacher, who was so used to me quickly grasping the concepts that she didn't really spend the time to explain the process to me, but also on my own stubborn refusal to let go of the first premise of my artistic pursuits up until that point, which was that everything begins with black lines on white paper.