Over the last decade, dystopian fics have been popular. There's the Hunger Games, Divergent, the Maze Runner, Unwound, When She Woke, and so on. The authors of these novels (and plenty more that I didn't mention) comee up with all sorts of unique worlds/scenarios, with some sort of plot device that caused the world to become dystopic (natural disasters, war, nuclear holocaust, religious takeovers, and so on) and thus the world, or at least a country, is created, or begun anew. Dystopic stories are one of my favorite sub-genres of fiction, but I am also a picky… er, discerning reader.
I will admit first off, that I am a plot Nazi. Ever heard of grammar Nazis? Sure you have. For me, I tend to focus on the plot and its background, and how well certain details or subplots of a story fit together, and if the framework/background is plausible. At the end of a book, if important questions are left unanswered (without a sequel forthcoming) my jimmies become rustled.
Among my writing goals is a science fiction universe (which will have at least one book in it) and as you guessed, it will be dystopic. I can't reveal details right now as I am still working out and mapping the aspects of this world. What I can say is that reading various dystopic novels, and being a plot Nazi, has helped me in my own world-mapping.
One major issue in some novels – not simply dystopic, but some sci fi works in general, or fantasy, is that when the author introduces us to his or her world, there are aspects of it that he/she neglects. Now, each story is different, so certain story or societal elements in each tale will receive more or less emphasis. Some tales may focus more on the difference between the rich and poor of that world. Others will focus on gender issues, or religious issues, relations with alien races, or so on and so forth.
An author needs to be careful to create a world that is sustainable and actually makes sense. They don't need to go into every minute aspect of this world they created, but they do need to do a lot of thinking and planning behind the scenes, to make this world be able to support itself.
One big example of an author doing it wrong is the Divergent series by Veronica Roth. I must warn you, there will be spoilers ahead for those of you who have not read the books.
In the Divergent world, which is set in our future, the United States as we know it is no more. There is this society which is ruled by five factions – Abnegation, Amity, Candor, Dauntless, and Erudite. The members of these Factions have traits which qualify them for their Factions, and each Faction has a duty to the city (which come with priilege) and there are certain jobs which belong to each Faction.
Abnegation, which focuses on selflessness, is tasked with the leadership of the city, since selflessness is seen as the best quality a leader can have. Amity, which focuses on living peacefully, is in charge of food production, as they work and maintain the farms which feed the city. Candor, whose trait is honesty and an intolerance of lies, serves as the lawyers of the city. Dauntless, which values courage, serves as the soldiers of the city. And Erudite, which values intelligence, are the teachers and scientists.
When I first started reading Divergent, I enjoyed the book and being introduced to this world. However, I began to see issues that would cause this society to collapse within itself pretty quickly.
People who do not have a Faction are basically screwed. They are second – heck, third-class – citizens, treated shabbily. Most of them are homeless, without means to support themselves. There is no mention of them having jobs, and Abnrgation gives them charity – Tris' mother does knitting and bakes bread for Factionless.
Children who are born to people in Factions may choose to stay in this Faction when they become 16, or transfer to a different Faction where they must pass an initiation to prove that they have the trait that is valued by that Faction. If they fail the initiation, they become Factionless. Nothing is said of the children that are born to Factionless parents, it seems that they remain Factionless their whole lives, having no chance at all to have a decent life.
As I pointed out, each Faction has jobs that it has provenance over. However, there are plenty of jobs which apparently don't exist anymore, like construction (many things in the city are in decay, potholes in the roads, etc. However, some buildings – particularly the ones that the Factions use or reside in, are maintained) So officially, jobs in construction don't exist because the Factionless are given no means to support themselves, yet someone has to do the construction/repair. There are plenty of other jobs that don't fit in the Factions, either – such as blue collar jobs, i.e. textile/clothing production, food processing, production of various goods such as shoes, containers, books, electronics, and so on. Veronica Roth completely neglects this vital aspect of society, simply dividing the world of Divergent into the haves and have-nots. The world of Divergent would not last a year with this system, as things would go to hell pretty bloody fast. (This society, according to the Divergent series, has gone on for about eight generations, or about 200 years, if I recall correctly)
No society is perfect. Hence dystopia, instead of utopia. But when creating a society, however oppressive or cruel it is, one has to consider how such a society and regime would be able to sustain itself for a meaningful period of time. In the society of the Hunger Games, Suzanne Collins created the country of Panem, and even though in the end Pamen comes to an end, Pamen had a system which lasted for 75 years (not including the years before the first rebellion) which included keeping the majority of the population poor and oppressed, and using the Hunger Games to keep the districts pitted against one another instead of cooperating.
Even though the oppression and cruelty of the Capitol came back to bite it in the ass (with some help from Katniss Everdeen) the fact remains that the regime of the Capitol was effective enough to keep the masses oppressed for 75+ years, and may have gone on longer if not for Katniss.
Regardless of what kind of story/world you create, and whether or not you plan to have the rulers/society of this world eventually come to an end, you need to lay a good foundation for this world.