READ READ READ READ READ!!!!!!!
by Nara
Seriously. This may sound like a stupid/obvious/useless tip, but if you think about it for a second, it really isn't. Writers have to learn from someone. So, read everything you can get your hands on. Fantasy, fiction, non-fiction, sci-fi, adult books, teen books... Read as much as you can. It helps you pick up on what works and what doesn't in a sentence, in a storyline, in a character...
Even if a book is bad, try to finish it. Think about why you didn't like it. Everyone always says that you must learn from your mistakes, and while I do believe that, I think it's just fine to learn from others mistakes too. Learn from other people's successes, as well - think about your favourite authors or books. Discuss them with friends, or even better, with other writers. What makes you like them so much? How can you use this in your own work?
There's a world of literature out there. Read and learn from the best. It helps you write and it can be a lot of fun. So make sure you never, ever forget to keep reading, because you never know what might happen when you open a book.