This one is just for fun. It is not really a lesson as I just dug up some past figure drawings to show you a couple of examples how I begin a drawing. Learning to draw in line to establish the structural elements of the drawing before including the value or color information is a great way to work out proportions and shape concerns first.
The first two are old drawings from I did when I was a student. I was learning to construct in line all the important structural elements before I went on to render the forms in full value. Click on the image itself to see a larger view. You can see I learned to map out a fairly thorough construction before continuing on.
This is an example of a painting I did a while back. As you can see I don't construct the figure as thoroughly as I did in my student work but I still rely heavily on those principles.