I'm not some great author...
But I've gone from an unpublished cautious scrub slowly and gently poking around for ideas and lessons on the internet, to a driven confident writer who ONE:
Knows what they want to say and TWO... Knows how to say it. Here's what this website and it's amazing people have taught me in the last year.
Write what you want, post it fast somewhere, and wait. ... Wait.
Let those critiques come in, and SHUT UP!
Let people tear your baby apart. Let them be honest. You need to learn to accept negative criticism. Let people tell you what they liked about your work, and what was wrong with it. Recognize when smarter better people are giving you good advice, and use it. There'll be positive feedback, sure. But pats on the back don't help you get better. Learn to thrive on advice that points out flaws in your creations, so you can get learn to write like a pro.
2. Write what you want:
What are you thinking about right now? What's in your head, right now, that piques your interest? Do you like TVs? Are you a TV expert? What about wines? Do you know the perfect wine to mix with late nights when the sun is still so hot it manages to light and warm the room through the blinds?
What consumes your thoughts when you're alone in the dark, because THAT'S what you should be writing about.
Don't follow market trends, or research Fandango for 50 shades of bullshit or hunger game knockoffs. Those people made millions because they wrote what they wanted, and they got rewarded for it. Write what you want, and you'll be writing something real and true and magnificent.
3. Write every day.
This may sound insulting and stupid, but I'm going to say it because some people need to hear it. To be a writer you need to want to want to write.
Andy Weir didn't write The Martian so he could sell millions of books and become famous. He posted blurbs on a blog because he wanted to write. It was something he did every day, because he loved the subject and the idea of conveying his love of space exploration through writing. J. R.R. Tolkein wrote a genre defining magnum opus as a side project he sent to his son before it ever saw a publisher.
Great writers are ten(10) steps ahead of their own fame. If you've written a masterpiece, by the time it's changing the world you're probably ten chapters into you'r 3rd book.
Because you're a writer.