John Ruskin 
The Seven Lamps of Architecture [EPUB ebook] 

Some years ago, in conversation with an artist whose works, perhaps, alone, in the present day, unite perfection of drawing with resplendence of color, the writer made some inquiry respecting the general means by which this latter quality was most easily to be attained. The reply was as concise as it was comprehensive—’Know what you have to do, and do it’—comprehensive, not only as regarded the branch of art to which it temporarily applied, but as expressing the great principle of success in every direction of human effort; for I believe that failure is less frequently attributable to either insufficiency of means or impatience of labor, than to a confused understanding of the thing actually to be done; and therefore, while it is properly a subject of ridicule, and sometimes of blame, that men propose to themselves a perfection of any kind, which reason, temperately consulted, might have shown to be impossible with the means at their command, it is a more dangerous error to permit the consideration of means to interfere with our conception, or, as is not impossible, even hinder our acknowledgment of goodness and perfection in themselves.