If you've written something that isn't in the correct perspective, it will leap off the page at you. Use the colored font feature on your word processing package to change narrative exposition to one color, action sentences to another contrasting color, description in a third, and so on. Study the distribution of the colors on the page. A majority of narrative exposition is not appropriate for any of the popular fiction genres available today. Be in this game for the long haul.
People do sell their first book, yes, but the odds are against it.
However, persistence is the most common weapon in a successful author's arsenal. You're not a failure until you quit. This way, you don't get caught up in the narrative and forget to check for typos. If you absolutely adore a passage of writing, it's a sign that the passage probably needs to be cut. Sorry, but you're more than likely hanging onto that piece of prose because you like it, not because it serves a fuction in the story or article.