The late Guy Boothby used almost to re-write his stories, after they were set up in type; the margins of most of the slip proofs being so covered with new matter and alterations that they had often to be entirely reset. So expensive did this become, that at last I decided to keep his typed MS. in a drawer for a week or two, and then send it back to him, asking him to do whatever rewriting was necessary before it was set up.
Of course, writers may alter a good deal in their first MS., before ever it gets to the publisher; but my experience has been that the author who worries his proof is the one who has previously worried his MS. (and sometimes his family too)! It is primarily a matter of mind-certainty, combined with the question of temperament.
One thing is undeniable: some writers will polish their MSS. into things of beauty; others will polish all the individuality and life out of theirs. In the latter case, however, I am inclined to think there was not much individuality and life to start with!
So far as the beginner is concerned, my advice is Polish; most of us can stand a good deal of this without losing anything worth keeping, or coming to a bad end!
To get under way, Start where you are
Do not waste time in waiting for something extraordinary or sensational to turn up, in the way of a plot, or you may have to wait a long while. Begin with some everyday happening and invest it with personality.
If you can, avoid making your early MSS. love stories. The dénouement of a love story is so obvious: try to write something on less obvious lines; it will be better practice for you.
Study some of the many delightful books that have been written in other than love motifs, yet dealing with events of ordinary life; such as The Golden Age, and Dream Days, by Kenneth Graham; A Window in Thrums, by Sir James Barrie; The Country of the Pointed Firs, by Sarah Orne Jewett; Timothy's Quest, by Kate Douglas Wiggin.
Genius is shown in the ability to take simple themes, and treat them greatly.