I just completed my 20th novel, and I've been putting together novels in the 100K range pretty quickly lately. I can write a novel of this size in about 1 month. This is working from 7:00 am to 9:00 pm a day.
Step one is getting the words on the page. As each chapter is finished, I review it and rewrite. I make notes at the bottom of the chapter about the next steps in the plot/story line. This means when the novel is first completed, it has been through a first draft and a full rewrite. I always use spelling and grammar checking in Word, and I note every suggestion--even if I don't take it! (This is true of readers too. If you don't like their suggestion don't take it, or better yet, fix the passage, sentence, paragraph using your own style--never ignore your reader's comments. You are free to ignore computer grammar checker comments--they usually can't handle most dialog etc.)
Step two is a full rewrite. This is the big fix it stage.
Step three is to hand the manuscript to my readers. I usually have two at this stage. They give me lots of help with punctuation, words, etc. and that is great--what I really want is continuity in plot and theme. I want to know where the work needs tightening and where it doesn't make sense. I usually get these comments/ideas from discussions with my readers.
Step four is incorporating readers' comments and fixes and a total rewrite. I usually have had a while to think about the work and recognize where it might need help. Look especially for missing descriptions and incomplete or illogical incidents or inappropriately foreshadowed events etc.
Every time I go over the work from that point on, I will make changes. Key things to look for are overused words, expressions, trite constructions, spelling, grammar, punctuation, cohesive forms of words (spelling of numbers, etc.).
Step five is getting ready for publication. When the work first comes to me as a formatted pdf, I read it quickly hunting for errors and checking the editor's comments. This is the first go through.
Step six is the long lingering review of the first formatted pdf. This is when I send it to my readers. I use three readers for review prior to publication. I know there will be more than one go around, so I send the results of my long review back to the publisher before I hear from my readers.
Step seven is the second formatted pdf review. This is when I incorporate my reader's comments and corrections, and then I complete a "read out loud review." Always accomplish a read out loud review prior to the final. You will be glad you did.
Step eight is to go around again--if necessary.
Step nine is accomplished with the final document. Pull the pdf into Word and let it check for spelling a final time. You can do this by opening it, or by copy and pasting it into Word. This is the last chance. At this point, you probably won't be able to find any more errors.
Step ten: don't read your own books--you'll find errors. I guarantee it. At this point, you probably don't want to ever read the novel again.