I generally sympathize with Matisse's view that artists should cut their tongues out so they won't be tempted to explain their work. It may not show, but I do try on this blog to avoid adding to the sum total of BS written about art in the world.
Here are some comments about the artistic process from illustrators or other artists that I think are particularly insightful:
Don't stop to admire a partly completed sketch.
On always doing your best work: The argument that "it won't be appreciated anyway" may be true, but in the end this attitude does infinitely more harm to the artist than to his client.
On being accused of making art like a madman: There is only one difference between a madman and me. I'm not mad
What one has most to strive for is to do the work with a great amount of labor and study in such a way that it may appear, however much it was labored, to have been done almost quickly and almost without any labor, and very easily, although it was not.
I ain't yet worked out whether I like girls because I like curvy lines or if I like curvy lines because I like girls.
-- some artist on the internet whose name I forgot to write down
On when to put the finishing touches on an illustration: The longer the idea can be considered in the abstract, the better.
There are moments when art attains almost to the dignity of manual labor.
-- Oscar Wilde