If you want to write for a living, probably the first advice you'll get is.. get off your butt... and write!
That's the toughest part, after all - getting started... doing it!
The voice in your head that argues with you when you dare to believe that you can succeed is your biggest enemy. It may come in the form of a friend's voice. It may sound like a parent, teacher, sibling or your dog, but that voice is really yours.
Once you decide that you are going to ignore the nagging doubt and just get busy writing... you are on your way to being a writer.
Try to remember that you are developing skills that will keep improving through your whole life. Talent needs to be nurtured. The same way that learning to ride a bike or do a back flip takes practice, becoming a great writer is not an automatic process. If you expect to score tens the first time you try a skill, you're guaranteed disappointment. Just keep writing and watch the reviews get better every day!
There are plenty of places to find tips and advice online and in your real life. Find them and listen to them. Fill the space around you will positive people who will help you to become the amazing writer you can be.
Learn more about what it takes to become a really good writer from other accomplished work by young writers or teen poets, or meet up with them in forums and online groups.
Surf around and discover expert fiction or non-fiction writing tips, career advice, ideas on what to write about, where to submit your work, and how to enter writing or poetry contests online...
Merlyn's Pen - Make the jump and submit your work for review by real editors.
Figment - An online community for teen writers and readers offering the opporunity to post stories, read book samples and reviews, or swap tips in the online forum.
TeenLit - Lots of good writing tips at the forum and online workshop, plus a chance to take over a volunteer job at the site.
Teen Ink - Fiction, non-fiction, poetry and more - by teens - for teens. Submit your work at the cyber home of the print magazine.
Write Source - Good ideas for writing topics by grade level, how to submit your writing to the site, and related links to other sites that may publish your work.
School Journalism - On the school paper? Check out this great site with a directory of U.S. state high school journalism groups, with tips on how to win a teen journalism award, links to high school newspapers online, a glossary of journalese, and other tips for moving toward a career in the news biz...