Read, and write, a lot. You learn to write by reading. You sharpen that craft by writing. One cannot be an Olympic-caliber athlete by sitting on one's bum. The same applies to being a high-caliber writer. It requires some talent, to be sure--but it also requires a certain degree of discipline in one's work. And having someone else read what you have written and offer honest critiques can be very helpful. Don't be thin-skinned about it; learn from what they tell you and use it to make your craft stronger.