Line weight is everything. Notice how the first panel looks darker than the second? Particularly the lady character? That`s because my hand was heavy and the line stroked too wide. That`s the downside of doing the work by hand — It`s not a simple button-click to undo (I have the left button on my Wacom tablet set to undo). I have White-Out (name brand, yes!) and it does a pretty good cover-up job, but then I have to wait and while it takes pigment from my technical pens well it doesn`t take ink very well at all. So, I end up fixing things with technical marker. I don`t think you can tell in the digitized product, but I can tell when I do it, and it feels like a real hack thing to do.
On a side note, I really liked doing this one and like the results. And yes, I know someone with a workspace which has a window like that.