The point of Nanowrimo is to write a lot, then come back and edit it later. Lots of people have trouble with this because they want to edit now. Editing as you go is fine if it doesn't stop you writing but as soon as I get into editing mode my productivity drops. I need to get the story out there first, then tidy it up later!
The secret is to deal with your inner editor. Some people send him or her on a virtual holiday but I've got a better plan: I pit my inner procrastinator against my inner editor. My inner procrastinator is strong and wins every time!
It looks like this:
Inner Editor (IE): That's terrible grammar.
Inner Procrastinator (IP): I'll deal with it later.
IE: This story isn't making sense.
IP: I'll deal with it later.
IE: Didn't she have green hair in the last section?
IP: I'll deal with it later.
You get the picture. The hardest part for me is going to be shutting up my inner procrastinator when November is over and I need to edit!