I've been a writer for more than half of my life. I have 2 filing cabinet drawers full of my middle and high school notebooks alone, not to mention all of the computer files that have been saved or lost over the years. (I used to keep my stories on yellow floppies because that's where Jenny Calendar stored the curse for Angel's soul on Buffy.) I know a lot of people scoff at me for being a self-published writer, but its not because I'm not any good. After 18 years I better be. :) But my reasons for self-publishing are for another post.
Because someone actually asked me for writing tips (hi @MsVSterling), here are some for new and aspiring writers.
1: Write for yourself first. Write what you want and how you want because if you don't love what you're writing it will not have any soul, and it won't be any good.
2: Good writing comes with practice. Just because you can publish a novel on your first try doesn't mean you should. *coughtwilightcough* When I look through that filing cabinet and read what I considered brilliant at 12, 16, 18, or even 28 all I see is un-publishable garbage. You get better every year that you write, so why not present at your best? It takes time to become good at something. (I'm not suggesting that you throw out all you write for the next 18 years, but writing steadily for one or two before attempting publication might not be a bad idea.) Take that time, and treasure it.
3. Expose yourself to good art. Not just books, but television, movies and music too. Read books that are well-written. Avoid cheap reality television--watch smart comedies and well-crafted dramas. Listen to music other than the top 40. Watch a movie that challenges your perception of the world. When you're immersed in good art it will reflect in your own work.
4. Don't be afraid of fanfic. Disapprove if you will, but Stephen King started by re-writing movies into comic books as a child. There are authors who've made entire careers out of re-working public domain stories. When you write fanfic you learn different styles and different voices. Your writing becomes adaptable and flexable. Also its a lot of fun and despite what naysayers think, doesn't really hurt anybody. It's a great way to 'practice' writing.
5. The phrase "write what you know" is garbage. If that were true all of my stories would be about borderline Aspie girls depressed about working in the restaurant industry. (Instead of sexy gay vampires.) Write what you're interested in and the knowledge will come with practice and research. (Yeah, you still better research.) Writing is about exploration and learning. There is always more to learn about the world and yourself.
So there's my inspirational speech for...probably the year. Hope it was helpful. If it wasn't, well, I'm just a self-published nobody. (But ask anyone--my fanfics kick ass.)