I always try to use Chekhov's gun, and often couple it with foreshadowing.

The unreliable narrator is a hard one to do well; I have only read a couple where it actually worked. I have never tried it.

MacGuffin is so much fun, as is the false progatonist.

I find the 4th wall break only works in a comedy or a first person PoV story where the narrator is relating the tale to the reader very directly.

But the thing I wanted to mention was the cliffhanger. A lot of the editors I have worked with indicate that this, especially in longer books, and utilising it at the end of chapters, is almost expected nowdays in action, thriller and horror works.