I cannot stress enough how important it is to have patience when aspiring to become an artist. So often we pick up brush or pencil, only to put it down for good when we're not masters right away. How many pieces turn out to be less than they could have been.
It's said to "get out your bad pieces first"; or to "get low-hanging fruit out of the way". Working - in the sense of going through boring, tedious parts in order to create beauty - can rarely hurt a piece. While there's also truth in keeping a piece fresh, intuitive, effortless, it's also true that this can only be done when you have a grasp of your tools and skill. Every artist needs mileage, no matter where in their career, which takes patience to gain, but it is invaluable.