And what else can go with it? (Which helps determine its length as I pontificated here.)
And this is where the smell of the story comes it. Its feel or its taste would be good metaphors as well, 'cause it's an entirely intuitive process.
I've got two outlines I'm switching off at lunch time. I was thinking about throwing a random piece of magic in one of them, and concluded -- no. It didn't feel right. This particular story needed a tightly built world -- even if not built, at least implied in a lot of mundane detail -- or its moral dilemmas would not be strong.
Now, the other one smells of magic. Very strongly. Mostly magical objects, I'm not sure there are wizards in it at all, but magical cobblestones and stairs, even, and more and more objects. Right left and center. In the first hour of the story the heroine gets to walk through summer, spring, winter, and fall. Which helps explain why the heroine starts off with two of them herself. Of course, what appears where is not quite so clear yet. Especially since there's some "stuff happens here" where the kidnapped heroine learns that the kidnappers are honorable men acting out of desperation. (This one has moral dilemmas, too, but they don't need the mundanity to work.) But I am looking for some magical objects that would give her a chance to learn.