In writing, there is no 'TRY' as the great Master Yoda is so fond of saying. You either 'DO' or 'DO NOT' write a book. Simple and true.
I have gone to many a conference and met people who where 'thinking' of writing a book. They chatted with me happily over lunch and even went on to 'pitch meetings' with agents and editors. Some of their ideas were downright awesome and yet a small percentage of those stories ever get written.
That is why although NaNoWriMo is going to produce some heinously cobbled together, practically stream-of-consciousness, monstrosities...it is totally worth it to participate.
Let me be clear. Getting something down on paper, however disastrous, is ALWAYS going to be better than never writing at all.
I once received some great advice from a writing mentor. He said that the first draft is supposed to be crappy. Its supposed to have flaws and plot holes and repeated words. Why? Because it is a 1st Draft. Just get the story out.
Embellish the setting later. Nit-pic the dialogue after. Weave in some more mystery or romance or zombies...whatever. But write the dang thing first. Finish.
There will be 2nd and 3rd drafts. Polished manuscripts you send out to Beta readers and to contest and agents.
The hardest thing to do is to put your behind in the chair every night and type until you hit your goal. And you have to have a writing goal for each day. Be it word count, page count, or chapters, you don't get up until you reach your goal. Period.
But if you are serious about becoming a published author there is only one way to do that. Write.
I hope to see you on the NaNo site! My handle is Rbyrnz. And may the words be with you.