Writers and would-be authors usually don’t have any trouble putting words down on paper. That does not mean that it can’t be improved, only that they have potential. No matter how much your Aunt Geraldine likes your stories or thinks you should be on the New York Times Best Seller list, chances are you have room for improvement.
Always strive to be the best writer you can be. Reading books by established authors published by well-known publishers usually (but not always) provides examples of outstanding writing and editing that you should emulate.
This is not to say that you can get there overnight. It takes years of study, practice, and coaching to perfect your style. Have confidence, but at the same time be humble enough to realize there is always, with few exceptions, room for improvement.