I say that in narrative paintings one should mingle direct contraries close by, because they produce strong contrasts with one another, and all the more so when they are very close together; that is, the ugly next to the beautiful, the big to the small, the old to the young, the strong to the weak; in this way you will vary as much as possible and close by.
Leonardo da VinciEvery now and then go away, have a little relaxation, for when you come back to your work your judgment will be surer. Go some distance away because then the work appears smaller and more of it can be taken in at a glance and a lack of harmony and proportion is more readily seen.
Leonardo da Vinci