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.
“To note an artist's limitations is but to define his talent. A reporter can write equally well about everything that is presented to his view, but a creative writer can do his best only with what lies within the range and character of his deepest sympathies.”