Note that there is a little eye icon on each layer. When clicked, it will toggle the Visibility/Invisibility of the layer. In this example, if I turn off the visibility of the Draft layer, the page will look like below:
Next I finally start on the actual tracing. This is done on the new layer created earlier on top of Draft. This new layer has the Composite Method of Gel. Aside from that, I change the line thickness to 1.0px, Freehand. Mind that I'm using a tablet, not a mouse for this. :p
As for the choice of Brush, 2B Pencil or Smooth Ink Pen would be cool. In this example, I will be using the pen.
And wheeeeeeeeee! There I go. After an hour or two into it, the page will start coming along pretty well. It is not uncommon for me go keep creating new layers (Composite Meth. = Gel) as I work. I do this because I don't want to mess up the foreground lines which I've done. Like for the leftmost panel below, the Madame will be on one layer while Diana will be on a second layer. All this can be merged or not in the end. More layers mean the bigger the file, though!
Partially
Traced Page
A
zoomed in version