With fanfiction, the writer of a movie, TV series, or book has already done the character building.
As the fanfic writer, you get to throw your favorite characters into different “what if” situations.
Plenty of Doctor Who fanfiction writers, for example, write stories bringing the 10th Doctor and Rose Tyler closer together.
Just how close they get depends on the writer. But a solid ship (i.e., pairing) can generate a slew of spicy fanfic ideas.
Fanfiction is a great way to build a devoted readership and develop your writing skills.
All you need now is a list of intriguing fanfiction story ideas.