Write. Sadly, a lot of things in life are just that simple. I'll ape Yoda here: Do, or do not. If you have an idea, write it. BOOM! You're a writer. You might not be professional, published, rich, successful, any of the words we place ahead of Writer when we make our titles, but you're still a writer. The field is full of BS artists who place a well-placed scarf ahead of content generation, which is infuriating sometimes, but in the end, if you devote time to WRITING, not looking like a writer but REALLY WRITING WORDS, then you are a writer. End of story. So my advice is to sit down a write.