Don't Give Up
Just like any talent a person has, the skill isn't mastered until lots of time has passed by. Yes, I will admit there are a few child geniuses where the law doesn't apply. For the most part, a professional in his field has took up time practicing, failing and getting up again. Do you think ballerinas just hopped up on one foot the first time they started to dance?
The same applies to any great writer. They may write thirty pages of simply nothing; then realize that they need to start all over again. Practice, practice and more practice will excel any natural capacity that the writer holds; therefore making them a genius in their own part.
The best advice anyone can give you is to not give up because someone tells you that what you have written is garbage. I say, "One man's garbage is another man's treasure. Keep writing and one day someone in the publishing industry will find value in your work; therefore launching your career.