I'm writing a book with a world similar to ours but at the same time is very different. I don't know how to do it smoothly without overloading the reader with information but at the same time giving them enough information so that everything makes sense.
This is a classic problem. It's especially true for fantasy and science fiction stories where basic facts about the history, culture, and science of this world are fictional and thus not familiar to the reader. But presumably this information is common knowledge to all the characters, so it would be out of place for them to tell each other. For one character in a fantasy story to tell another, "Ruritania is a large country on the continent of Freedonia" would be like a character in a story set in 21st century America telling a friend, "The United States is a large country on the continent of North America".
This problem isn't specific to fantasy and sci-fi; it can be true in any story. How does the reader know that Fred is a policeman or that Bob and Sally dated in high school? Etc.
Common solutions include:
- Have characters lecture each other about what the character already knows but the reader doesn't. Have them begin by saying, "As you know ...", and then proceeding to explain what the person already knows and the speaker knows he knows.
This is pretty lame and writers are continually warned against doing it.
- Include a character who does not know what everyone else knows.
Many fantasy and sci-fi stories include a character from 21st century America travelling to this time and place, so that he knows pretty much what the reader knows and anything else has be be explained. He has a rational reason to ask the same questions the reader would ask, etc.
Great if it works in your story, but often it doesn't.
Another popular idea is to have a scene where a teacher tells school-children about history or whatever information.
In my humble opinion, this sounds like a good idea but rarely works, because the school-room scene usually has to be rammed into a story where it is totally out of place. A character who is not a teacher suddenly shows up giving a "guest lecture" at a school for no apparent reason. Sure, sometimes it works. If you have Captain Kirk teaching a class on military tactics at Starfleet Academy where he describes how the last three wars with the Klingons went, yeah, I can believe that. But when you have Captain Kirk show up at an elementary school to give a lesson on Federation history, sorry, that strikes me as very implausible. Even if you come up with some justification -- his orphaned nephew asked him to play his dad for "parents tell kids about their jobs" day at school or something -- it will likely sound contrived.
I recall a movie, "Harrison Bergeron", that has a scene where a teacher is quizzing the class, and one student has all the answers while all the others sit silently. This allowed the movie to both tell us the sci fi history, and also tell us that this young person is such a genius that it is causing him social problems, at the same time. It was still a bit strained, I thought, but a good try.
- Introduce small amounts of information in an off-hand, indirect way. Real people don't lecture each other about the other person already knows, but they might mention a fact that everyone present knows in order to make a point. Like I wouldn't expect Captain Kirk (okay, I've got Star Trek analogies in my head now), sitting on the bridge of the Enterprise, to announce to the crew, "I am captain of this ship, the Federation Star Ship Enterprise." Presumably they all know that. But it would not be silly for him to say in a conversation, "Since I became captain of the Enterprise, I have had to deal with a lot of problems worse than this revolt on Rigel 7." Now we know that the character is captain of the ship, the ship is called the Enterprise, and there is some sort of revolt happening on Rigel 7, without anyone having to lecture about these things.
I recall a movie about a computer crime (forget the title) where one of the criminals has a girlfriend who knows nothing about computers, so they periodically have to explain things to her.
- Explain the information narration. Interrupt the action briefly to tell the reader what he needs to know. This is simple and straightforward and doesn't involve any strained dialog. Writers often avoid this because it can be boring and it breaks rules like "show don't tell". Personally I think writers avoid it too much. I much prefer a story where the narrator just tells us the necessary background information, rather than coming up with implausible reasons for characters to tell each other.
Like with so many non-mainstream settings or ideas, just present it as normal. Give a minimum of information but allow the reader to figure much of it out.
Many works use the troupe of using a naive character as a stand in for the reader. While this sometimes works, it's also overdone and usually fairly tedious. Only do this if there is a really good reason to have a naive character there. And don't have other characters explain everything to her/him.
Sometimes just a few words is all it takes to explain a radically different setting. For example, instead of a long infodump about the effects of having two moons, maybe have a couple kids laugh at the families at the beach who didn't plan on it being double-moon tide and getting all their stuff wet.
A wonderful example of how to do this is The Golden Compass. That world is like Earth in many ways, down to the British college system. And at first the book doesn't seem like fantasy. Then the author matter of factly mentions "daemons." The word is puzzling but then the reader sees it means visible energy manifestations into animal shapes, something that every person has exactly one of. Yep, not our world. It goes on from there, getting more and more fantastical with every page.
One of the best methods I've used to introduce a new idea in my fantasy writing is to use a character POV who is foreign to the concept and get introduced to it by someone who is well-versed in it. It would be too obvious to put that character into a lecture about it, and it would be boring. But, you can make those characters journey together for a bit, and the idea gets introduced in simple ways, bit by bit. The dissemination of the concept would feel natural if you create human interaction that feels natural. Don't give away too much but give enough to leave the reader with a taste for more.
A good example of this would be Gandalf's occurrences in Frodo's journey. You don't know a whole lot about his powers but enough to know he's very powerful.
Vampires and werewolves are such a staple of folklore that introducing the reader to the fact of their existence can be done in many ways.
In Interview with the Vampire a nervous journalist saw something he couldn’t explain and learns about vampires from a world weary vampire.
Perhaps your MC collects the various items that are said to be weaknesses of vampires. His home might have many mirrors, garlic hangs from his door and festoons the kitchen. His picket fence looks remarkably like a series of stakes hidden in plain sight and he never invites people into his home.
You could mention the various things he collects and the reader will probably start wondering if there might be a vampire in the closet.
Perhaps a neighbor who watches too much television or reads gothic novels stops by and wonders if the man is preparing for vampires. He might even joke about it.
Drop hints about why your MC is in on the secret - was a loved one killed? Did he witness something that changed his life?
Moonlight did it well - a private investigator who works at night and has some odd quirks because he a vampire living among us.
In Forever Knight, the MC is a detective who is a vampire and his partner learns the truth - and that there is a hidden subculture of vampires in the city he thought he knew so well.
There are so many vampire/ werewolf tales out there that you can be rather subtle and build to the first time it is crystal clear that there are other species among us. Your reader will probably figure it out rather quickly.
Prey took that and gave it a twist - a new species of human that is stronger, faster and smarter than homo sapiens. The enemy was evolution.