I’ve been using Artur Guptill’s Sketching and Rendering in Pencil recently. Quite an informative book, especially if you don’t have an academical art background, like me.
The first part deals with the importance of painstaking accuracy in line drawing. I feel I sometimes lack the speed I need to quickly measure and report big shapes of what I draw. Therefore, following his example, I took an old shoe of mine (though it’s not so worn out) and drew it. The full drawing took a lot, like 4 hours, to be completed.
I first blocked in the big masses, constantly taking my drawing near the subject to compare it. It’s useful to strive for precision just by eyeballing, as I noticed measuring too much with the thumb on the pencil is not only time consuming, but not precise enough to base the drawing on it.
p.s. Yes, those strings have been a pain to copy.