I'm going to participate this year. I did it last year as well and it was a lot of fun. To answer your "How do you go about it?" question:
I'm doing the whole planning/outline the story/taking notes about characters and setting thing on a mighty piece of software called Scrivener. Scrivener is available on Windows, Mac and Linux (beta version, completely free). It really helps you to organize your writing! There's a free 30-days trial and it's really easy to export your work at the end of it if you're not convinced.
I do my writing itself on FocusWriter, a minimal, distraction-free, highly-customizable, feature-rich text editor. It's completely free and available on all platforms.
Lastly, I use DropBox to sync and save my writing between all my devices and in the cloud. It's very useful as it will always keep a copy of both files in case of major differences between two sync. DropBox's basic plan gives you 2GB of storage for free, and it also allows you to access your document on your Android or iOS phone.
(I also use a spreadsheet to keep track of my wordcount, but you can find hundred of those on the web.) As far as pieces of advice go, there are countless of them on the Nano forums, so my biggest tip would be: sign up on the website and read the forum! You'll probably find a forum for your very own region, where other crazy-minded writing people organize write-ins and other various nano-related events. Depending on your style, you may fall into one of three categories: - a plotter (someone who outlines and prepares the hell out of their work before starting to write on November 1st, who has all their characters described, all their scenes planned, and so on) - a pantser (from the phrase "flying by the seats of one's pants": you haven't prepared anything and you just start writing whatever comes to mind on November 1st) - a mix of the two above (most people). The NaNo forums cater to all three. You may want to read all the resources you can find for the next couple of days - after all, you still have a solid three weeks before November. If you have questions, feel free to ask them!