My writing has become much cleaner, more focused. I'm very intolerant of people who use exclamation points in every other sentence. Get rid of all those ridiculous horrible adverbs and adjectives. We owe it to the readers. It has not gotten easier, however, just because I've written so many books.
Every book is different.
What changes is style. All of us started out as story-tellers. But we have to get more polished. We should all get more streamlined. Nobody knew anything about publishing.