A reminder here, you can hire a line editor - proof reader (I know a good one if anyone needs one). But there is more to being a good fiction writer than grammar and punctuation. A perfect, error free ms isn't necessarily a good read. There are elements of the craft that are more important than the occasional subject/verb out of agreement.
A fiction writer needs to practice the skills of the craft: Character Development (not a two paragraph mini bio that stops the story dead - boring), pacing (sentence structure and context that matches the action of the words), scene (the development of vignettes that drive the story forward and develop the characters, create conflict and resolution), setting (only stand up comedians work on an empty stage - put people in the city scenes and animals in the rural scenes, and a habitat to match the setting), tone (the flavor of the story, the aftertaste), voice (who tells the story, the 'personality' of the storyteller - not the writer), literary devices (personification, foreshadowing, dialogue, backstory, and more), plots, plot arcs, and subplots, tense, point of view (POV) - see the links below for more info.
Notice I did not mention once that to be a good fiction writer you need to know the 48 prepositions or the 8 parts of speech (The basic eight parts of speech in the English language consist of the verb, noun, pronoun, adjective, adverb, preposition, conjunction and interjection.)
Writing fictioin is like building a house. You need to have electrical, plumbing, structure, design, a roof - the paint and floor covering are last. Novice writers try to paint before the walls are up --they edit prematurely.
I've put together some books on writing on the third page of my amazon store
http://nadinelamanbooks.com/astore.html If you buy only one book, buy the script writing book. Read the parts about camera angle and the parts that teach you to write a motion picture in your reader's mind. There are several other books I like, I'll ask Joyce - my web designer - to add them for me.
If you are editing while you write or right after the first draft is finished, it will show, it will not be your best possible work - I read far more mss than I read published books. I can tell at what stage the editing was done and your eventual readers will too, even if they don't know what is lacking. While editing is important, it is far less important than good writing...and that comes with rewrites. Basically, editing for grammar and punctuation is the last step of polishing an ms.
Writing a good story is the first step, that is why I say the elements of producing fiction are these in this order:
First draft - written from beginning to end, straight through, no going back at all - ever.
Rewrites - strengthening the story with literary elements of good story writing, done correctly, this step will be repeated several times - straight through, beginning to end.
Edit - cleaning up grammar and punctuation. And finally, line editing or proof reading.
From there you can query agents, shop your ms, or move into one of the many ways to publish your own book.
The saying goes: "Writers write" not "Writers edit." Don't get off track on what it is you wanted to be when you started writing, you wanted to be a WRITER.
Literary devices:
http://www.ask.com/questions-about/Literary-Deviceshttp://olc.spsd.sk.ca/de/resources/litdevices/index.htmlhttp://en.wikipedia.org/wiki/Literary_techniquehttp://www.uncp.edu/home/canada/work/allam/general/glossary.htmms = manuscript
Goodness, google 'literary devices' learn the craft, it is far MORE than editing.