As soon as I see the clip of the RAF guy on the news advocating that his troops grow beards to get respect in Afghanistan, I jot down a drawing, quickly, with a trusty felt-tip pen:
Now, I'm in a rush so I don't want a lot of palaver and I can't be arsed reaching for the lightbox so I quickly trace the thing on a new sheet of cheapo typing paper using a non-photo blue pencil, but I add a little more detail:
At this stage I would just ink it and scan it into the computer as the scanner can't see the blue lines unless I scan in colour, so no need to erase and risk fading the lines or tearing the paper.
As I said though, I'm in a rush so I scan in and change the drawing to 'gray scale' and darken the lines a little and then, again because I'm rushing, I draw with the mouse in Photoshop and put some basic lines in place - remember this is just a rough.
Just as soon as I 'merge' this bad-boy (the colour layer) with the rest of the drawing. And there we go, took about 10 minutes in total, but the finished drawing will take longer, providing it gets the nod, of course. Meanwhile, I have my blue pencil sketch ready for possible changes, and inking, and suddenly I'm ahead of time, rather than behind.