My current WIP has basically a sci-fi or possibly horror plot, but when I workshopped the first chapter, some of the readers were a little confused that the sci-fi theme didn't really hit them right away. The first scene makes it seem like the novel is more a love story or a redemption story. About 3,000 words in, I first introduce the idea of something a bit otherworldly (which was what seemed jarring to my readers), and the real sci-fi plot doesn't really take off until probably 30,000 words in.
That 30,000 word point might be the part where I want to start reading!
(Up to that point, the character is basically opening up the Pandora's box that is the sci-fi part).
Do you think that the theme of sci-fi or horror needs to be more obvious from the get-go? I mean, if you're writing about contemporary characters living in the world as we know it, who are maybe just scientists or interested in technology in some way, is this sufficient background that a reader won't be shocked when otherworldly events start happening?
I think the characters being scientists or "interested in technology" would likely clue me in enough, but it's hard to say. If I were reading I'd expect/hope for a "hard SF" story, but I guess I'd be in the minority of your readers.
While this doesn't apply to your story since its in the present time and all, I recall a "Heinlenism," - slip an idea in that tips off the reader that the story is SF - Heinlein's example: "The door dilated." Googling that phrase (in quotes) brings up many interesting webpages. Where was I ...
But I think if you have your characters get into a really geeky argument or two, such as the applicability of Maxwell's equations to a single electron (thus throwing a heavy dose of quantum mechanics into the mix), that should certainly tip off the read that it's gonna be SF.
Since Pandora's box is a story from Greek mythology, wouldn't that make it the fantasy part?
I took the phrase Pandora's Box less literally, to mean a bunch of 'odd' things show up that weren't there before, not explained in the story where they show up. It would be whether these things have a reasonable explanation ("scientific") or not (Who knows? This way-out crap happened!) that would determine whether it's SF or fantasy.
Perhaps the same writing up to and including that point could go either way, and be interpreted by different readers differently, and the real "SF or Fantasy?" question doesn't get resolved until later - perhaps either some prankster genius has invented some good hi-def live-motion holograms, or some
prankster magician is casting lots of spells some ghost/soul is stuck on Earh and making these things happen for some reason (it has something to say, and these odd happenings are the only way it has to communicate with living people?).
Hmm, maybe for NaNo I should shoot for a 50,000 word OUTLINE of a book.