Character refers to dispositions and habits that determine the way that person normally responds to desires, fears, challenges, opportunities, failures and successes.
I don't think anyone is ever writing so that you can throw it away. You're always writing it to be something. Later, you decide whether it'll ever see the light of day. But at the moment of its writing, it's always meant to be something. So, to me, there's no practicing; there's only editing and publishing or not publishing.