So you want to be a writer? Or is it that you are writing but not getting anywhere? You read books, take classes, attend writer groups, read blogs about writing, and still something is missing. What can I say? That happens. Writing is a skill and some people are better at it than others. I play the guitar, but I'll never perform for anyone; I'm not good enough and I know it.
What can you do? Write more. You'd be surprised how much writing you need to do before your skills develop to the point where they are good. You need to read a lot too and notice how sentences are put together. How does the writer get your interest and hold it. How are characters sketched and developed.
But even after all that, there are some things you are going to have to learn on your own. For example, you need to know what tone a story should have. I can't teach you that. And you need a voice all your own. I can't teach that either. These come from experimentation and experience I'm afraid.
Use of repetition is another one I can't teach. Oh, I can tell you not to be repetitive and you'll be able to do that. But sometimes you need to break the rules. I can't tell you when or where to do that; you have to feel it -- yes, this is the writer as Jedi school of learning, thank you -- and know that you've got a good place to use it.
You also need to develop an internal sense of when your story is good enough. Most writers don't have this to start. I certainly didn't. But you need this so that you know when to send it out for others to look at. If you send it out too soon you'll get rejected and discouraged. But if you send it out when you know it is ready, then each rejection you get can be weathered and not throw you off course.
I had this problem. Publishers want to see your work but not until it is ready. If you've got flat characters, it is not ready and you need to fix that first. Of course, when you think the story is ready but the publisher doesn't, you wonder why the universe is conspiring against you. The simple truth is: you need to revise your story.
Of course once it all comes together, writing a good story is great.
So keep at it. Writing takes time and patience and a clear head. Know what you want to say, know your characters, and know the world your characters are in. And try writing some non-fiction first to get all the grammar, punctuation, spelling, and mechanical issues out of your writing. When you've got that down, you'll be ready to starting fiction.