I was fortunate enough last summer to speak with Bruce Coville at an SCBWI event in Orlando. (He's an amazing speaker—truly amazing—and if you catch word that he is speaking somewhere, by all means go and see him.) Bruce mentioned something he called "The Rule of Twenty." He doesn't recall where he picked it up—a business article? a self-help book? a primer on original thinking?—but wherever it came from, I have since relied on it and relied on it often.
What is it? Put most simply, it is this: It is only when one reaches the twentieth or so idea that one starts entering the realm of the truly original idea.
The first five or ten? Those are the obvious ones that the brain goes to along its well-traveled paths. Most people's heads will go that way and think of that thing. (Are you disappointed when you can see the plotline of a movie from a mile away? That's thanks to the filmmakers working the shallows of the Rule of Twenty.) In the teens, you are starting to bushwhack into uncharted territory, where most people's brains rarely go (because they are not as focused on craft as, say, a writer is). But by the time you hit twenty, you've likely discarded all the obvious and nearly obvious, and now you are working in a territory that is peculiarly yours. Those ideas you've worked toward will have the snap of the real and a complexity that speaks volumes.
Bruce was talking about the naming of things—characters, realms, books, what-have-you. Names are hugely important in fiction, of course, and our most beloved writers are masters of naming. But naming is about much more than simply giving a place or a character a telling handle, it is also the way the writer establishes his or her authority, where the writer becomes the author, if you will. Is the name too simple? Too easy? Too telling? Does it have hidden qualities?
Can you imagine Dickens without Magwitch or Havisham or Pecksniff? Rowling without Hogwarts or the Weasleys or Snape or her latinate spell names? Dahl without Trunchbull or Augustus Gloop? Pullman without the aletheiometer or Iorek Brynison or places like Bolvangar? The naming here does important work—so much so that a lot of exposition can be left out. Thanks to etymology, we know that "panserbørne" in The Golden Compass means more than simply "armored bear" (the Danish translation)—we hear echoes of Rommel's panzer division, and there is an instant military air to the term. (Children won't necessarily hear that, but that's okay—the name is dark and rich and has extra dimensions folded within it.)
But naming is only one part of it: The Rule of Twenty can and should be used to consider plot twists and any other part of writing a story when you suspect you may have taken a too-easy route. Chances are that you have. So push yourself, reach that twentieth idea that is yours and yours alone, and see what you end up with.