Lillian Bell
edward_sledge
Planning is fine, you just can't start the actual novel.
Well technically you can
start it, you just can't count the words you wrote before November 1st. I plan on writing the beginning ahead of time, because they're always so hard to get into. XD
NaNoWriMo.org FAQ
Do I have to start my novel from scratch on November 1? Can I use an outline?
Yes.
This sounds like a dumb, arbitrary rule, we know. But bringing a half-finished manuscript into NaNoWriMo all but guarantees a miserable month. You'll care about the characters and story too much to write with the gleeful, anything-goes approach that makes NaNoWriMo such a creative rush. Give yourself the gift of a clean slate, and you'll tap into realms of imagination and intuition that are out-of-reach when working on pre-existing manuscripts.
Outlines and plot notes are very much encouraged, and can be started months ahead of the actual novel-writing adventure. Previously written prose, though, is punishable by death.
So
technically you can't start it, if you want to follow all their arbitrary rules. However, I'll admit that last year I carried my GothNoWriMo project over for NaNo, but only counted the words I actually wrote in November. Choosing to disregard the rules is different than not knowing them.