I'm in the middle of editing the last two novels in the Shadowkill trilogy, and I've come across something that may be helpful to fiction writers: as early as possible, create a character list as you write.
This may seem like a no-brainer to some and a "oh I don't need that; I'll remember all of my characters" to others, but trust me when I say that for most, you'll thank me later.
No matter how minor a character may seem, it's good to jot their name down and maybe add a note on how they're relevant. About a third of the way through book 2, I discovered I had a different name for an extremely minor character. I didn't have a note on this one.
This list doesn't have to be some Wikipedia page or anything. Just a name and anything relevant to the story.