Not to want to say, not to know what you want to say, not to be able to say what you think you want to say, and never to stop saying, or hardly ever, that is the thing to keep in mind, even in the heat of composition.
The seeing of things as they really are — the seeing of a proportion veiled from other eyes (together with the power of expression), is what makes a man an artist. What makes him a great artist is a high fervour of spirit, which produces a superlative, instead of a comparative, clarity of vision.