Obviously, you may want some way to keep the focus of your story on your narrative, and figure out what comes next in the story. Some people like keeping extensive notes to help them stay within a strict narrative, or keep tabs on where they think the plot should go next. Others, such as myself, prefer to wing it all the way and make everything consistent later. Both have their pros and cons, obviously. The strict narrative idea makes the whole process easier, but if you choose to stick with it to the end, you won’t be able to use any great ideas you had later. The seat of your pants style, while more fun in the short-term, in my opinion, is more annoying in the long-term, especially if your characters’ personalities shift down the line (especially if they shift multiple times. Trust me, I know), but it does allow for more creativity, and new ideas that simply improve the story overall. What is best is ultimately up to you, however.
Thinking about it, the best approach, if you can use any approach you want with equal efficiency, is probably somewhere in the middle. Keep certain areas strict while leaving others flexible (and now I see why I shouldn’t write posts on my netbook. Can’t see the whole post at a glance. Oh well, live and learn). Still, this will involve some rewriting, because, as you’re writing, your writing style will probably shift as you find your voice, and get used to using it.
Tomorrow I start on the next series, which is all about characters. And there will be a lot to say about that. In fact, it’ll probably be the first one requiring multiple posts for single subjects. Definitely a good reason to stick around and see what I can come up with.