I highly recommend picking up "No Plot No Problem" by Chris Baty and reading it either now or at least by October. There's also a "kit" that can be loads of fun, if that kind of thing appeals, but definitely get the book. Also, I've found that sticking with the daily word count is one of my best tools - also writing more the day before taking a day off rather than taking a day off and trying to play catch-up.

But the biggest thing? Recruit friends. Seriously - and preferrably at least a few offline as well as on. Check out any local write-ins that may be scheduled. (They're loads of fun if you've got a good regional liason.) I dragged my best friend in kicking and wibbling and it was really an awesome boost and incentive to get stuff done.

Let me know what your screenname is on NaNo when you sign up and I'll be sure to add you to my buddy list there as well. :)