Little cliffhangers. Very small cliffs, but lots of them. All going on at once, but layered. My friend Rey (whose manuscript I'm currently re-reading) does it very well. And the writers of Veronica Mars (which the girl and I have been devouring on DVD) also excel at it.
But it's tough for me. My natural impulse is always to just let the story flow, uninterrupted, not manipulating the reader with these tricks, meeting any expectation almost as soon as I set it up. Even though I know, know, that it makes for better storytelling when you do play this game. Hopefully someday, this will become secondhand for me, but for the time being it's another thing I have to keep juggling around in my mind while trying to write.