1) Write in 500 word chunks, 4 per day. Should only take 20-30 mins each. One first thing, one at lunch, two in the evening with a break.
2) If you write less than 1700 words one day, don't stop until you've written 1700 + double the difference the following day. That way, when you're thinking of giving up for the day you know you're getting double the work for your reward.
3) Buy yourself a reward and dangle it. I just got hold of the Lost season 3 boxed set, and it's sitting above my monitor, sealed. I won't allow myself to watch it until I write the 50,000th word for Nano. If I don't write 50K, I won't allow myself to open the seal until 2008.
4) If you fall behind, look up my NanoWrimo 7500 words in one day catchup form/article
5) Turn the TV off. If you have to cook/clean/do other chores, make them brief.
6) No sharpening pencils.
7) Delete your email and web browser icons from the desktop/start menu. Force yourself to go through C:\Program Files\etc to find and run them.
8) Each evening, after you've written the daily 2k or so, outline a few scenes for the following day.
9) Write the scenes which interest you, not necessarily the next scene in order.
10) Don't be afraid to branch out. If your plot changes, leave a note in the text and keep going.
This is my third Nano, by the way. I completed it in 2005 and 2006, and I have every intention of doing it again. I'm not a particularly fast typist (I don't really touch type - although I don't have to look at the keyboard) but I manage to do my 2k per day or else.
Simon Haynes is the author of the Hal Spacejock and Hal Junior series (Amazon / Smashwords / other formats)