Writing fiction is almost always a process of successive approximation. In fact most of the goodness in most people's writing comes from rewriting.
One of the most valuable skills a writer can learn is how to rewrite aggressively. That is, how to go through a piece and make every word in every sentence in every paragraph justify its existence. If it's unnecessary, it comes out. If it doesn't convey exactly what you want to say, you need to change it. Write it and then rewrite it and rewrite it and rewrite it until it's as good as you can possibly make it.
This is a difficult concept for a lot of beginning writers. Our society teaches us to think of inspiration as golden and that we don't want to stifle our creativity. As is so often the case our society is, if not utterly wrong, then seriously misguided.
The hard fact is that we tend to try to substitute creativity for almost every other virtue in everything from art to business. However there are a lot of other factors which are at least as important as inspiration. One of them is the ability to work with that inspiration until it gives the very best results you can manage.
People who are overly concerned about stifling their creativity by reworking what they do are usually doomed to failure. In the case of writers they're typically not very creative either.
Of course the other, unstated, reason for the bias against rewriting is that rewriting is the pick-and-shovel labor of writing. It is unglamorous, hard work and often frustrating. It can ultimately be extremely satisfying, but that's frequently difficult to see at the time.
Now granted, some days it just flows. Everything that appears on your screen is golden and you wouldn't change a word of it. I'm here to tell you that such days are extremely rare. If you get one or two paragraphs like that in a day you're doing well.
The other characteristic of successful writers when is comes to rewriting is that they're ruthless about it, more ruthless than most other people are prepared to be in dealing with their prose.
Once, a number of years ago in an online discussion group, three of us edited a paragraph of fiction. One of us was a copy editor, one of us was a book editor and one of us (me) was a writer.
The book editor made a few changes that made the piece a little better. The copy writer made a few more changes and the result was even stronger.
As for the writer, I butchered it. I reduced the whole paragraph to two short sentences and it was a lot stronger for it.
The lesson is that as a writer you bear primary responsibility for writing and re-writing your work. You can't depend on other people to fix it for you.
People sometimes ask me how many rewrites I do. Depending on definition the answer is anything from 'none' to 'hundreds'. For me rewriting is an integral part of the process, not a separate step. Whenever I hit a flat spot, I stop creating prose and scroll back through what I've done so far, rewriting as I go. Similarly if I need to make major changes I tend to do them before I finish. I may not do a second draft as such, but by the time it leaves my hand every word in every pieces of fiction has been gone over multiple times.
Books on writing often warn beginning writers against the dangers of excessive rewriting. In my opinion such advice is misguided. First, the problem most writers have is that they don't rewrite enough. They leave their sculpture rough and unfinished because by the time they get to the end of the project they're so sick of it they just want it to be over.
The second reason is even more important. The problem with 'excessive' rewriting is not excess; it's quality. Bad rewriting is just as deadly as bad writing.
The mark of bad rewriting is change for the sake of change. In other words, the inability to critically evaluate what you're looking at and see what will make it better, as distinct from what will merely make it different.
Always, always, the question is "does this change make it better?" If you can't honestly say yes, then don't make the change. The exception is when you're taking things out. Because so much writing is overly verbose my instinct in considering a questionable cut is to make it. Similarly if the change makes the piece longer, I am very cautious about making it. I want to make sure that the added words will carry their weight in the piece.
This kind of critical thinking isn't always fun. In fact sometimes it smacks of strangling a baby in its cradle. But whether it's fun or not it's essential to produce a finished work of fiction.