The difference between a thriller and other genres is the tension that the story creates. It’s very fast paced, and the characters don’t usually engage in a lot of introspection, so you have to have a story that is conducive to high action and high tension. You want to make sure that the conflict is going to allow you to create the necessary tension between the antagonist and the protagonist. Some stories don’t lend themselves to that, so you want to make sure that you’ve got that down before you start.
One of the most important parts of writing a thriller is point of view. A lot of authors aren’t even aware of what that is. It’s learning how to tell a story from a given perspective, and there are rules about how to do that (of course, you can break the rules if you know what you’re doing). Being able to maintain a character’s point of view really well allows you to create the tension that gives the thriller its thrill. So once you know you’ve got a good story, the next most important thing is to go out and become schooled in how to do point of view really well. Point of view lets you use the information that the reader doesn’t know to create tension. For example, if the good guy knows everything that the bad guy was doing, and therefore the reader does as well, there’s no tension, because there’s no chance for the good guy to walk into a trap. So it’s the lack of information that actually creates the tension. Writing from a very narrow point of view lets the reader feel uncertainty along with the protagonist.
I had a tense experience recently—I was out camping with my boys, and during the night we were chased out of our tent by an animal. At the time, I thought it was a black bear, but it turned out to be a cougar. The point is that part of the reason the situation was so tense was that I didn’t know who my adversary was or what it was doing. If I had known, I would have had a better idea of how to respond, and the situation would have been less tense. In the same way, restricting the reader to the protagonist’s point of view adds tension to the story.
Another good example is the movie Jaws. Originally , they were going to have the shark in all of the scenes and the audience was going to be able to see it, but the technology wasn’t all that great and looked corny, so they ended up keeping it off screen. It turned out that decision made the movie a lot more tense, because you can’t see the monster but you sense it’s there and you don’t know where it’s coming from.
That tension is about all that holds the reader’s attention in a thriller, and if you can’t create it, you can’t get deep. There’s no love affair that’s really driving the story; there’s no philosophy or introspective element to it. All you have is the tension. If you can’t tell the story from a narrow point of view, tightly using all five senses, then it will just fall apart, and the reader will read a couple of pages and then get distracted by an iPod or something and move on. So point of view is one of the cornerstones of being able to tell a good story—especially if it’s a thriller.