As developing a story, your main character must face conflicts as attempting to resolve the central problem that set the story in motion. These conflicts, however, must always relate to that central problem. Such conflicts are called complications.

For example, suppose the central problem of your story is that a sheriff in the Old West must track down a bank robber. Any complication in the story would be a conflict that hinders the sheriff’s ability to catch the bank robber: he loses their trail; his horse throws a shoe that slows his chase; he must enter a canyon in which he could be ambushed. Unrelated conflicts, such as wishing the pretty young teacher in town wouldn’t marry the general store’s owner might be interesting, but at best that will just be a subplot unless it can be connected to catching the bank robber.

Each new complication also needs to create a more dire situation for our main character. This does not necessarily mean that each new conflict is more dangerous than those that came before. Instead, with each new complication, the prospect of resolving the central problem becomes more unlikely or will require some great sacrifice on the part of the main character.

Complications need not just be external conflicts but also can be internal. For example, the sheriff might doubt his own abilities, perhaps because he didn’t catch a bank robber when serving as a sheriff back East, and the deep sense of failure is what led him to head out West. A horse throwing a shoe is certainly a problem, but one the sheriff easily can overcome with time; he just needs to make it to a blacksmith or a local rancher who knows how to shoe a horse. The sheriff’s uncertainty about what to do next, however, can lead him into more difficult troubles…for example, once he picks up the trail again, he might doubt and second guess his discovery and set off in the wrong direction.

As developing complications in a story, always ask what is the character’s driving motivation for solving the story’s central problem. Then have the antagonist play off this by foiling the main character in some way related to his motivation. For example, in an espionage tale, our protagonist spy’s motivation for solving the central problem of stopping a terrorist from exploding a dirty bomb might be loyalty to and love of country. Have the terrorist plant information that suggests the spy’s own government is behind the dirty bomb plot. Now the main character must unravel the truth and wonder if his loyalty is misplaced, all while the terrorist continues unhindered in hatching his dastardly scheme.