Congratulations! If you are at this stage of your writing, you used all the big tools and completed your haiku/story/novel, are now ready for the final touches. With this draft, the heavy lifting is over, and you can get out the writing tools of finesse: Sandpaper and Files (not Word files, but the actual hand files). A few warnings about these. First, do not use these before you are ready, as doing so can be a dramatic waste of time. Second, wear goggles, because you can get stuff in your eyes and they'll water up with tears.
Too often, I have seen writers get hung up on that eternal question, "How do I know when it's done?" It's not like a cake in the oven, where that little browning on the edges tells you it's time. Rather, you have to tell yourself, "This is where I want it to be," and you go with it. This often starts with asking yourself, "Does this piece say what I want it to say?" "Are my ideas fully communicated?" and "Do I feel comfortable with the outcome?" Being able to answer all those questions in the affirmative means putting away the heavy gear and focusing on making each part smooth and fancy, with every description and metaphor shaped just so.
Another problem that comes with the sandpaper and files is temptation. For some writers I know, they create the first chapter of their novel and they want to sculpt it to perfection. They want to put in all the detail work and sand off all the coarse edges so they will know that the first chapter is, in fact, completed. That's how they feel their process should work. I won't say that's a terrible idea (although I believe it is very much a terrible idea), but I will point out that the other tools I have discussed in past posts can wreck all that detailed work with one swing.
Think of that ideal first chapter - introducing your protagonist and a group of friends. There's an engaging conversation, a big event, and the call to action begins! Great first chapter - off and running. You shape and finesse every bit of dialogue, hone every detail and sculpt every image with the intensity of Michelangelo. Then you go on to chapter two. Well done. However, there's every possibility that by chapter seven, you realize one of the characters in that first chapter is dead weight, another character should be female, and certain plot details need to be introduced. This forces you to make a tough choice: undo a bunch of that polished work or stick with what you have at the expense of a better story. The choice is obvious from this perspective, but when you are deep into your writing process and heavily invested in your labor, the choice is not so obvious.
Putting together any piece of writing is indeed a daunting task, and the time and effort required is often more than one expects. However, going in with the right tools makes it a lot easier, and knowing how and when to use them really moves the job along.