The approach to drawing - real and imagined

[Thistlegorm]

Now, I'm a pretty new guy, and I'm working and seeing progress, what I realize however, is that there are a couple of different approaches to drawing, for instance:

1. Plumb Lines: http://www.wetcanvas.com/Community/i...10-suedemo.JPG
2. Thinking in shapes/form http://www.explore-drawing-and-paint...l-shapes-1.jpg

The information I couldn't find is not how these approaches work, but how they differ, what purpose each one has - I can appreciate that there is no "correct" way to approach a drawing; but from your personal experience, how do either of these methods work for you? What are you able to do with one method that you can't do with the other?

Personally, I'm trying to force myself to think and break down in 3 dimensional shapes as opposed to plumb lines (I figure it'll teach me how to draw from my imagination), but since I'm a beginner my results aren't reliable enough to draw(hehe) a conclusion - this is where you guys come in

Feel free to mention any other approaches

[Elwell]

Requoted for the umpteenth time:

Drawing is a complex process, which requires the artist to continually switch between several different modes of thought, depending on which one is useful at that particular moment. If I'm drawing or painting a figure, for instance, sometimes I'm looking at it as an abstract collection of flat tones and shapes, sometimes as a collection of three-dimensional forms in space being effected by light, sometimes I'm thinking about the names of the bones and muscles and what they are doing, and sometimes I'm thinking about what my artistic intention is with the piece and how I have to interpret and modify what I see in order to fulfill it. Training that leaves out any of those modes of thought is incomplete. Making art takes your whole brain.