One other suggestion is to never self edit as you write. This will only slow down the writing process and frustrate you. The best thing is to write without worrying about grammar and punctuation or spelling until your particular section for that days completed. The next day when you go back to it then you can more clearly see any errors and you can quickly edit at that time. This not only such splits your writing up into manageable chunks but also splits up your polishing and editing so that you are not doing it all at once.