Everything I write is original to me. But on writing forums, I always hear people complaining about cliches and it seems every single thing I write about is something that everybody loathes by now.
"Oh my Gawd! Female protagonist! So overdone!"
"Oh my Gawd! A quest! Ew yuck yuck trite!"
"Oh my Gawd! A person thrown into a strange world and forced to become a hero! Snoooorrrrre!"
"Oh my Gawd! Etc. etc. etc. every single little thing bla bla blarggh blagslghsdlf!"
I always find it perplexing because even though I know such things have been done, I haven't read those stories, so my own writing isn't directly influenced by that--I'm just writing MY story the way MY story goes--and it doesn't matter what the heck I'm writing, there's always a big group of people ranting about how they'll never read something like that again because it's SOOOOOOO TIRED. And yet people keep reading such stories! See how they fly off the shelves despite critics' insistence about how trite they are.
But the weird thing is, the people who've read my stuff, I rarely ever hear any complaints that what I've written is trite or overdone. Even though my main story features a female protagonist, a quest, and an unwitting hero thrown into a strange world, things which you'd think are the bubonic plague to a lot of people nowadays.
My point, I'm not entirely sure about my point. I guess it would be that when I'm writing I don't even bother stopping to think of all the times this must have been done before (and if I do think about that, I think in terms of archetypes, not cliches). I just write my story the way my story needs to be written, and if it features something that a hundred people insist has been done to death, well, too bad. Since I'm writing it the way I feel it should be written, and I'm not focusing on how cliched this aspect might be, I like to think that helps me write it more original--it just seems that the more you focus on how cliched a situation is, the more likely you are to commit the very cliche you're trying to avoid, or else you'll just stall out altogether for fear of committing it. Either way you lose.
You say you're working with an editor, and you already know that most things have already been done, so I'm not sure how helpful anything I said was. I think one should just write their story the way their story demands to be written, first off, then look to see if the cliches are as horrible as they seem or if they've been diminished in the process. A lot of times cliches vanish once a story is done because the writer has put their own original slant on things, and they just couldn't see this at the beginning. Sure, I write some cliches. But they're not cliches to ME personally--*I* haven't written them a hundred times over--and I enjoy writing them, and it's the way my story has to be told, so hopefully they don't come across as the cliches so many people claim they are. (The very few cries of cliche I get on my own writing? They're usually from people who read like one chapter/story and then wander off. Hardly representative of all my writing.)
Not sure if that made sense. :/ Maybe just stop trying to avoid cliches, and just try to write the story? Though you've probably already tried this since you say you didn't have this problem at one point. Sorry this isn't very helpful.