I use Scrivener, and then manually back-up to a memory stick. I was going to use Dropbox, but the Scrivener site said that Dropbox sometimes re-orders your files & folders according to it's own rules, and that can disrupt the way Scrivener works, so it's good for backups but can cause problems if your try to work off of those files.

Oh, I also wanted to point you at a wonderful series of posts I just found on the Guardian website, How To Write A Novel In 30 Days. This is the first post, which links to worksheets you can use to help you with the process:

http://www.guardian.co.uk/books/2012/oct/20/how-to-write-preliminary-outline

And my perennial favourite, How I Went From Writing 2,000 Words A Day To 10,000 Words A Day:

http://thisblogisaploy.blogspot.co.uk/2011/06/how-i-went-from-writing-2000-words-day.html