I just finished reading the Sanford Green Interview on the Character Design Blog. They asked him if he had any tips or wisdom about being an artist and what he said I thought was worth passing on:
Work hard and take nothing for granted. Be on time and study your craft. Make a decision on where you want to go and work as much as possible to get there. Even if it takes years. Also surround yourself with other artist that's just as good as you or even better. All that does is keep you humble and hungry.