In his book Textual Poachers: Television Fans and Participatory Culture, academic Henry Jenkins includes a section detailing ten different ways a show can be rewritten as a Fanfic. In an abbreviated form, these are:
- Recontextualization - Filling in the gaps in broadcast material and providing additional explanations for characters' conduct. See Fan Wank and Fix Fic.
- Expanding the series timeline - Either into the past or future. See Continuation, Prequel and Backstory.
- Refocalization - Shifting attention away from the program's central figures and onto secondary characters (often women and minorities). See Day in The Limelight and Lower Deck Episode.
- Moral Realignment - Inverting or questioning the series' moral order. See Deconstruction/Deconstruction Fic, Alternate Character Interpretation, Perspective Flip, Die for Our Ship and Draco in Leather Pants.
- Genre Shifting - Telling stories different in tone and style from those of the actual series. See Characterization Tags, Dark Fic and WAFF.
- Crossovers - See Crossover and Fusion Fic.
- Character Dislocation - Characters are removed from their original situations, and may be given alternative names and identities. See Alternate Universe Fic and Transplanted Character Fic.
- Personalization - "Mary Sue" stories, and stories that break the fourth wall by having characters interact with fans. See Mary Sue, Marty Stu and Self-Insert Fic.
- Emotional Intensification - Including the "Hurt-Comfort" genre. See Hurt/Comfort Fic.
- Eroticization - See Lemon, Lime and Porn Without Plot.
Of course, these are rules for fanfic. If you're a pro, just stick 'em on a rocket.
If you are interested in more ideas about writing fanfiction see So You Want To Write A Fanfic.