I did the cross hatching using pencil on paper. The biggest problems I had was keeping the pencil sharp (cross hatching really wears the point down quickly), not smudging the drawing (I used a piece of paper under my hand to help though I forgot too many times) and trying to get some of the detail in some really small areas (bricks, window frames, doorways, etc.).
I noticed when I finished (which was a bit under an hour) that the clouds were probably too big making the scene seem top heavy. Digitally, I could have fixed that easily but with pencil and paper, I did not feel like erasing all that area. BTW the picture is on a 9" x 12" sketchpad page.
