"It is often said that Leonardo drew so well because he knew about things; it is truer to say that he knew about things because he drew so well." (Kenneth Clark)
I have been working on a HUGE order. It seems as if it has been going for years. by the end of a huge order I am getting drawing fatigue. Every piece has to have the same level of attack and commitment in the mark making and it is hard to maintain this, your hands and mind gets tired.
"The process of drawing is, before all else, the process of putting the visual intelligence into action, the very mechanics of visual thought. Unlike painting and sculpture it is the process by which the artist makes clear to himself, and not to the spectator, what he is doing. It is a soliloquy before it becomes communication." (Michael Ayerton)
It's really worth persevering with this approach though....or else you end up with meaningless marks.
"To 'draw' implies everything the word stands for: to pull or to drag or to draw forth, as from the earth, a vein, or well. (Lance Esplund)"
Emerson wrote the quote below referring to drawing as in "bringing out" I think it can apply equally to the intimate process of discovery in rendering a bird's nest in oxide and underglaze onto a porcelain surface.