Back in the art school (UiaH) I used to work a lot with charcoal. For a very long time it was my favorite material. Normally I would start by blackening the whole paper, then doing the drawing on top of the blackened paper and then starting to open up the light areas. Now with markers I notice I use the same idea in many panels. This is perhaps most obvious in some of the back covers. This manner of working seems to suit me especially well. Sometimes working with markers and scraper board this is a bit risky, there is a limit to the punishment the board can take, but it pays off.