I'm a big believer in improvisational writing. By this I mean, writing without having a clear idea where I'm going. I may having a general idea -- a crudely sketched out plot, for example, -- but I don't know the details before I start writing. I do this to see where I end up. Once I'm done I go back and keep what I like and discard the rest.
This approach is not for the novice writer because it is fraught with pitfalls. For example, you have to have a good sense of your characters or you cannot pull this off. Likewise, you have to know the background of your world well enough that if you invent something new on the spot that it doesn't create an inconsistency. Continuity is king.
I tend to write new scenes in whatever novel I'm involved with in this manner. Sometimes is works and sometimes is doesn't. Other times I can't tell if the new territory I've discovered will work or not. Those are the hardest pieces to assess.
Example: in Book 2, Evan pursues the trail of the necromancer who has abducted Duke Wrightwood by using the portal stone the dark mage used to transport His Grace back to his lair. When Evan arrives he finds a grassy knoll with a building at the top and a murky lake at the bottom.
Now I knew there was something in the lake. Something deadly. But what exactly was not clear to me. So I improvised and before long I had a battle scene on my hands as the multi-tentacled monster reaches out and grabs several of the knights who accompanied Evan to the knoll. The scene by itself is okay but I can't help feel it could be better.
I think part of this stems from the fact the monster is reminiscent of the scene in Lord of the Rings outside of Moria. A multi-tentacled monster attacks the Fellowship as they enter the dwarven stronghold.
I could change the monster, of course, but without a clear idea as to what the monster should be I'd be spinning my wheels. But that's the nice thing about writing. even as I write this a glimmer of an idea presents itself. Which only illustrates the fact that revision is key when using this technique.
Keep writing everyone. I have a revision in my future.