So you have a post-apocalyptic story you want to tell? They can be great vehicles for not only personal but social expression, often more so than other SF subgenres. Like most fiction, post-apocalyptic tales are influenced by the current zeitgeist — but also bring something else to the table: a reappraisal of the past and how it influences the present.
During the Cold War, most of those narratives focused on the aftermath of a nuclear conflict; now, we see more stories about climate catastrophes or deadly epidemics (zombies usually fall under the latter category). The mechanism for apocalypse may change, but the themes remain largely the same. How these themes are presented is crucial to exploring this subgenre. Without them, your story may be little more than an adventure with crazed gangs chasing the protagonists across a run-of-the-mill wasteland.
What follows are the essentials of a post-apocalyptic story. I went for macro elements; these can be found in a variety of such stories. Station Eleven by Emily St. John Mandel; The Drowned World by J.G. Ballard; the video games Horizon Zero Dawn by Guerilla Games as well as Fallout 4 by Bethesda; The Walking Dead comics by Robert Kirkman; and the film Mad Max: Fury Road by George Miller exhibit all of these qualities.
1. The Past must be Ubiquitous
What gives a post-apocalyptic story its flavor are the glimpses the writer provides of that world’s past. Ruined cities, old signs advertising products that no longer exist, technology that seems alien or even magical to survivors who are ignorant of its function — these are typical tropes, but they are effective. What makes this subgenre work are the contrasts between the survivors’ society and the civilization that preceded it. What does a character think of a society where she lacks electricity, but discovers traces of an older one that possessed such power? Or one where she has to hunt for food, whereas the former civilization featured well-supplied supermarkets? The contrast could highlight the scarcity of the current era versus the abundance of yesteryear. It could also reveal the ancients’ hubris or prejudice: were certain people prohibited from living in a designated area, or did a former religious institution forbid the mixing of ethnicities or classes, rather than the more open…