I've recently completed chapter one of my paranormal fantasy, NIGHTWATCH, and as I've gotten some early feedback, the story has been morphing from my original idea, which is a good thing. But as I change things like the character's age, which changes her experience level, this makes changes to the plot.
Originally I wanted the character to have years of experience behind her, but now she's only five years removed from the event that gave her power, and still struggling with everything that has changed in her life. This totally altered the plot of the book. I've been able to keep the core conflict, but the side plots have all been scrapped, because they simply don't work anymore (IE: vampires. Buh-bye vampires.). However, I do think they'll fit into sequels - if I ever get that far - so I'm saving all my notes.
So this morning, I tried a trick that I've seen mentioned in a few how to write novel books and posts. Namely, even though your book isn't even finished, try writing a query as if it were. It really puts a spotlight on what your main character's primary emotional story arc is, and what the main conflict is.
So I wrote a three line teaser blurb for my story this morning, and the words "desperate" showed up, and "redemption".
This excites me! Now I have my story's theme: Redemption, and I have my character's main motivation, Desperation. I vaguely knew I wanted to include those two things before I wrote the story blurb. But after writing it, I see that I haven't been infusing the prose with those two things yet.
And that's okay. I can go back in rewrites and tweak. But as I move forward into chapter two, I'll have this in the back of my mind and I know my story will be stronger for it, because hey, desperation just oozes urgency, and urgency is good for plot.
NOTE: Please, please, please, if you want to try this technique, keep the query for yourself as an exercise only. It is a huge no-no to query unfinished novels to agents and editors. I know I shouldn't have to say this, but... just in case you had the urge. Resist!