First off, thanks. :)
As for NaNo, hmm. Well, to get the minimum 50k, you'll need to write an absolute minimum of about 1667 words a day. That's roughly two pages of single-spaced, 12-point font. (You can also abuse your word processor's word count feature to help you keep track.) Now, this can be done throughout the day. For me, I can sit down, write that amount within a couple of hours, and then go do something else, but you really don't have to write in one long spurt. In fact, by all means, take breaks and everything so long as you eventually sit down and write your 1667 words.
If it helps, there's no-distraction tools designed for this kind of thing. Writing Resources has links to a couple of them. (WriteRoom if you have Mac, Write Or Die if you need a timer, a list of links to alternatives for WriteRoom. I personally recommend using Q10.)
For a third tip, try not to delete anything you write. NaNo encourages quantity over quality, and they've said explicitly at one point that it's okay if you end up with a crappy novel. Besides, you can go back and edit after the challenge, but either way, deleting scenes will probably cost you a couple hundred words.
Fourth, if it helps you, it's definitely okay to make a few notes on what you want to do. That'll help keep you focused and serve as reminders for what else to talk about. (I say "if it helps you" because some people, myself included, like derailing our own notes.) Definitely do this as you're writing, too, especially if you hit that daily minimum early. Getting yourself to think about what comes next in the story will help you figure out what you want to write for the next day.
And finally, I personally think joining NaNoWriMo's official forums and hanging around with other writers in the genre you're writing in serves as great encouragement. They're really an awesome community, and they've got a lot of interesting tips you can try in a pinch.
Hope some of this helps, and don't be nervous. ;D You'll do fine, and hey, even if you don't make it to 50k, you'll most likely have fun trying. (I know I do. Never hit 50k myself because November usually involves me writing a lot of papers, but it's always been a fun challenge at the very least. So, in other words, if you don't make it to 50k, you're in good company. XD)