Thrillers are about tension and movement, long odds and fighting to overcome them, and a hero so brilliant and determined that they win despite everything being stacked against them. They may have to make a big sacrifice, but in the end the hero saves the world.  Thrillers are usually written in third person, specifically, in third person limited. It’s a visceral genre, so first person is good, too, but thrillers often feature complex and/or convoluted plots that need several viewpoint characters to work. For first person, make sure your plot is on the simpler side, the twist demands the reader...