The best thing is to always keep honest people around, because when you have a bunch of yes men around that know that you're making a mistake but let you go on with it, that's when it ruins your mind state as an artist.
“Your memory is a monster; you forget - it doesn't. It simply files things away. It keeps things for you, or hides things from you - and summons them to your recall with a will of its own. You think you have a memory; but it has you!”