The three vital things needed by a writer are knowledge, experience and imagination. One may have all the knowledge and experience but if one doesn’t possess the imagination to ‘package’ them into readable form, then one cannot succeed in writing for long. Of course, time spent on polishing sentence structures too helps in the long run.
It has been remarked by someone that a part of the writer is in his or her writings too. Maybe, I think that’s what gives liveliness to a writer’s work.