1. A beginning with an action scene that seems unrelated to the main plot, but in the end you realize is.
2. A beginning that sets the tone for the rest of the book, whether by incident, setting, or character mood.
3. Extreme detail in world building so I feel like I'm actually in the place and care about that world.
4. Carefully placed adjectives, metaphors, and similes. And I especially love when these are unexpected but fit perfectly, ones that make you alter your thinking of the description because they are so not the normal, over-used ones. (The Book Thief by Markus Zusak seemed to have a lot of awesome ones, though some were just strange and pulled me out of the story and made me focus on why he said that.)
5. Relatable characters. Need I say more? Okay, I will: I love a character who has at least one trait I can sympathize with.
6. An action-filled middle. But not gratuitous action--scenes that really feel pertinent to the main plot.
7. A twist in the end that I think I've figured out until the author gives me a surprise head-fake. I love that because it leaves me wanting to immediately go back and reread the book to look for the clues I might have missed.
For the rare person who reads this blog, what are your favorite author devices? :)