Inception is a brilliant movie for many reasons, but the most profound and often over-looked reason is that it is the perfect blueprint for how to write a science fiction film.

Take the second scene of the movie, in which Cobb and Arthur are trying to break into Sato's mind. They encounter Mal-whom we don't know is a dead projection of Cobb's mind yet, so we assume she is a real person as well, and someone to pay attention to. This is the first rule to writing a good sci-fi story: Control the rate at which you reveal information to your audience. By withholding information on how subconscious projections can enter dreams, Nolan creates a level of suspense about Mal, as the audience wonders who she is and why she's ruining everything for Cobb.

It is also in this scene that the first bits of information on how the rules of dreaming work are revealed: If someone dies in a dream, they wake up. But if they don't die, they can feel everything as if it's so real that they are awake. This includes pain. Very quickly, Nolan has established how one can escape from a dream and what the stakes are when one is in a dream, and he does this in a very illustrative fashion by having Arthur shot and experiencing intense pain in the dream so that Cobb is forced to kill him to wake him up.

When writing a sci-fi story where the rules of the world are different from the rules of our normal world, the rules need to be clear and simple. Controlling the rate at which you reveal these rules allows you to play a game with the audience, keeping them guessing at what's really possible in the story and what isn't.

Nolan plays the ultimate game with the audience when he establishes the rules for differentiating the dream world from the real world with the spinning top. By not showing whether it keeps spinning or if it topples over at the end, Nolan leaves the ending for the audience to decide: Is Cobb dreaming or not? A masterful technique to use in writing sci-fi movies is establishing the rules and then handing them over to the audience to decide where the level of reality lies.

The easiest and clearest way to introduce all the rules of the sci-fi world you're creating is to give the audience a reference point, i.e. a character that knows nothing so everything can be explained to him/her. In The Matrix, it's Neo, who learns everything from Morpheus. In Inception, it's Ariadne, who learns everything from Cobb and Arthur. It's an easy trick to employ, but it's also dangerous. Notice in The Matrix and in Inception, as these characters learn all the new tricks of the new sci-fi reality; they experience all of these rules. Crazy and dangerous things happen to them. Many novice writers fall into the trick of explaining rules without showing them, creating a boring and often confusing introduction to their world.

By far the most important rule to follow for telling a good sci-fi story is the same rule to follow for any kind of story: create compelling characters. The audience is invested in Cobb getting back to his family as they slowly learn what happened with his wife and how it's partially his fault, making him incredibly relatable. If you don't have interesting and engaging characters, it doesn't matter how interesting your concept is, you've got nothing. And, you will find, it's creating compelling characters that's more difficult than figuring out the rules of your sci-fi concept.

Create compelling characters. Create clear and simple rules for the audience to follow. Introduce those rules to the audience by introducing them to a character in the story that knows nothing about them, but do it in an engaging way that makes it compelling on an emotional level. The easiest way to do this is to create real stakes for the character learning these rules. And control the rate at which you reveal the rules so you can play with your audience and get them to tap into their own imagination.

Do all that, and you've got the next great sci-fi story.