Now that I have finished the first draft of my WIP, I’m ready to start outlining it.

I’ve never understood how writers outline their stories before writing them. Sure, I could make up an outline before writing the draft, but my characters won’t feel any obligation to follow my plan.  And character sheets – I’ve heard about them, too. But I don’t know my characters very well before I start the draft, and they don’t usually turn out to be the people I think they will be.
It’s only now that GRUNSDAY is finished, for example, that I understand how Jax has to change over the course of the story, and the kind of person Evangeline needs to be from the start, and why Riley did the things he did.  Now that I’ve completed a draft, I’m ready to sit down and write character sheets – arcs for their personal stories.  In the case of Jax, the event which slaps him upside the head and forces him to change his behavior is one that was never in any of my plans for the story.  In fact, it almost didn’t happen.  I was just finishing the draft of the relevant chapter when I saw the opportunity and went back and inserted it on a whim. I don’t know if I should do this or not, I remember thinking.  But going forward, I immediately recognized the difference — how Jax had to man up because of that event.
It was 20/20 hindsight.
I’ll also outline all the chapters with color codes for the plotlines. (Katie Mills, you gave me that idea!) This will help me with pacing, because I know this story loses its way in the middle, especially now that I’ve seen the end.
World building? I’ve got to take care of that, too.  Now that I know what must happen, I can better define the rules of this reality. I made it too easy for my characters in the first draft. They are going to lose a few conveniences in draft #2, because if Grunsday is just like any other day, then what’s the point of writing a book about it?
I’ve got a short story project I need to work on while I mull things over and outline the current and future drafts of GRUNSDAY, but I hope to start revising before the end of the summer.
What kinds of things do you understand better after you’ve written the first draft?