Hallmarks of YA fiction: Love triangles – It's the problem we wish we had in high school: two gorgeous guys fighting for one girl's attention. Young adult books abound with love triangles, and the "Twilight" saga (with, from left, Taylor Lautner, Kristen Stewart and Robert Pattinson in the movie versions) was one of the first to start this ongoing trend.
Hallmarks of YA fiction: Dystopia – "The Hunger Games" was one of the original dystopian series, featuring futuristic, dark settings where teens battle the odds (or adults) to save humanity. Veronica Roth's "Divergent" trilogy continues in this vein with weapon-toting, butt-kicking heroine Tris Prior (Shailene Woodley on the big screen).
Hallmarks of YA fiction: Paranormal – Whether you're into vampires, werewolves and mermaids or zombies, shape-shifters and fairies, paranormal plots have long been a fixture of young adult fiction. Margaret Stohl and Kami Garcia revamped the witches trend in their Southern Gothic "Beautiful Creatures" series.
Hallmarks of YA fiction: Good vs. evil – It's usually pretty easy to tell the good guys from the bad guys in young adult fiction. This tension often takes the form of a "good vs. evil" struggle, such as in Cassandra Clare's "The Mortal Instruments" series about Shadowhunters with angelic powers (Lily Collins played heroine Clary in the movie). Naturally, not all the Shadowhunters use their powers for good.