Take your work seriously — ideas that come to 14-year-olds often lead to breathtakingly creative work later, and it's good practice even if the work you do turns out not to be publishable. Don't ever think that it doesn't matter how well you write because you're just a kid. Instead, write as if you had to live from your writing — take it that seriously. And never, never throw anything away. Even if you hate what you wrote last year, five years from now you might find value in it that can be salvaged. Remember that there is no embarrassment in last year's work. You always did the best you could with every story at the time you wrote it, and no one can do better than that!