I must respectfully voice a counterpoint to the "excessive organization beforehand is just a waste of time, get it written" opinion. For some people, organizing everything before beginning is not an indulgence - it is a necessity.
I absolutely cannot finish so much as a short story unless I have index cards written out detailing every scene, even some details of setting and character that I know I want to put into each scene, etc. Then, when I have everything organized on index cards with absolutely no blank spaces or question marks, I spew out a near letter-perfect first draft in an obscenely short amount of time.
I developed this system because I have almost no patience for rewriting. So I do the "rewriting" beforehand: throwing out cards as I realize that scene doesn't belong, reading them over and over until, by the time I sit down to write, I am more transcribing a story that is already playing out in cinematic detail in my head than creating a story there on the paper.
I admit this is extreme. But before I adopted this method, in ten years I wrote about a thousand first drafts that were not remotely salable, and not one second draft. I find rewriting to be nearly impossible, unless it is a directed rewrite at someone else's command. Once my words are on paper they just "sound right" to me. So if I don't get it darn near right the first time I'm pretty much helpless until some external person firmly directs me with an order such as, "change it so the guy gets the girl in the end" or "take out all the swear words." Experience as a freelance copywriter has made me very "directable," but I absolutely cannot rewrite my own stuff. Don't know why.
The good side is, that whole thing of "the story just went in a direction I couldn't forsee and set me back three months" thing? Never happens to me. All the chaos and creativity goes into my index cards. By the time I'm writing actual copy, the story has "settled" into what it's going to be for all time. Sure, sometimes I waste my time setting up a series of scenes on cards that turns out to be completely useless, and have to throw out the cards and make all new ones, but it takes a lot less time to summarize a scene on a card than it does to grope for just the perfect prose to describe it in your draft.
This isn't to say that I don't get some interesting surprises as I write my draft, but they're more along the lines of, "Wow, I didn't realize these two characters were attracted to each other so strongly" or "Wow, I didn't realize this guy was so funny" than "Wow, I don't think this plot is going to work, I'd better think up a new ending."
That said - the technique that works for you is the technique that results in finished, salable manuscripts. If this is your first novel, there is absolutely no way you can know what technique that is yet. I suggest you read Jack Bickham's book on writing short stories (if it's still in print) if you want to understand the way I write my novels and short stories, but there are a thousand other books on other techniques to get novels and short stories written, as well. Just keep trying things until you find one that works (i.e. gets the project finished).