It seems to take me an age of working out till I can start to see the finished lines.
I remember in a Steve Rude Sketchbook there was a section where he'd put some of his older work. In it you could see a mass of lines underneath the more finished drawing. His newer work had far less of these preliminery lines and he said that he had just come to a point where he knew where to put the finished line.
I'm hoping at some point I'll suss it out too, for now it just seems I have to draw a ton of lines until the drawing starts making sense to me. What I've put up here is an initial rough from my sketchbook that is pretty small. I then blew this up to the images print size and light boxed it through in blue. Again though I need to do a load of work to start to tighten it up and when I blow this upto artsize I still think I'll need to do some more before I can ink it, it's a hard life eh?