The young man should first learn perspective, then the proportions of objects. Next, copy work after the hand of a good master, to gain the habit of drawing parts of the body well; and then to work from nature, to confirm the lessons learned.
Leonardo da VinciIt should not be hard for you to stop sometimes and look into the stains of walls, or ashes of a fire, or clouds, or mud or like places, in which...you may find really marvellous ideas.
Leonardo da VinciA bird is an instrument working according to mathematical law, which instrument it is within the capacity of man to reproduce with all its movements.
Leonardo da VinciYou will never have a greater or lesser dominion than that over yourself...the height of a man's success is gauged by his self-mastery; the depth of his failure by his self-abandonment. ...And this law is the expression of eternal justice. He who cannot establish dominion over himself will have no dominion over others.
Leonardo da Vinci