There is a profound difference between prewriting, writing, and editing, which is also called revision.
Prewriting is all the things you do when you are getting ready to write a novel. You figure out at least who the main characters are, where the novel takes place, the plot and major subplots, and how the big finish is going to happen. At this point, your imagination has totally free reign, and you can create anything you can dream up within the confines of your skull. You are creating a new world—a place for your characters to live, work, and play—and hopefully, to get into a lot of trouble so there will be a good book to tell about their adventures.
Writing is just that; writing down the adventures your characters are having. Sometimes, this doesn’t follow the plan you made during the prewriting process. It’s all right if it doesn’t; it’s generally a sign that you have strong characters who are busy telling you their version of how it happened.
Revision is the final stage of novel preparation. This is where you check to make sure the grammar, spelling, continuity, and point of view are as close to perfect as you can get them. This is where you make sure all of your sentences aren’t too long or too short or incomplete, and everything works together to make a good novel great. The difficulty arises when the brain creating the book is the same one revising it. Sometimes, you may get tangled up in what portion of the book you’re working on. During the prewriting and writing segments of the work, let your imagination run wild. Come up with crazy ideas and run with them. Enjoy the process. You are absolutely forbidden to censor yourself with thoughts such as, “this is crazy”, “this will never work”, and “this is stupid”. First drafts are always filled with crazy, stupid things which will never work. That’s why we call it the first draft.
Put away your inner editor. What’s an inner editor? It’s the little creature who sits on your shoulder whispering that your book is crazy, stupid, and will never work, and furthermore, you’re just plain daft if you think you’ll ever write something useful. Smack him. Smack him so hard he falls off your shoulder. There’s a time and a place to use your inner editor, but the first draft is not the time nor the place.
Imagine this: You’ve completed all of your prewriting, and you sit down to write your novel. You write the first paragraph when you notice a spelling error in the first sentence. You go back and fix it. Then you notice the sentence is really too long, so you break it into two sections and add a few words to make it two complete sentences. Next, you notice the second sentence isn’t a complete sentence, so you need to fix it. You move on to the third sentence and do a little polishing. Then you decide your main character should have brown hair, rather than red, so you fix that. You could spend the next week polishing and editing this one paragraph to death, and you will never finish the story.
Finish the first chapter. Then write the second chapter, and the third, and all of them. Get your entire first draft written before you do any editing at all. Then it’s time to pick your inner editor up off the floor, dust him off, and make use of his talents.
If you really can’t get him off your case, then here is your assignment: draw a picture of the loathsome little creature your inner editor would look like if he was visible. Mine is a little puffy thing with six hairy legs and a cluster of eyes on the upper surface. Sort of like a crab, except he’s green and yellow and has leathery skin. Then either crush your picture and throw it in the trash, or draw big jail-type bars across the front of it, effectively getting your inner editor out of your way until the first draft is written.