One common theme is the exploration of their relationship growth. Since in the movie their relationship was just budding, fanfics often focus on how it develops over time.
One popular 'Clueless' Cher and Josh fanfic is 'Cher and Josh's New Beginnings'. It focuses on their relationship post - movie events and how they navigate college life together.
Well, a 'clueless novel' might be a story where the protagonist is constantly in a state of confusion. It could be that the author wants to show the character's journey of self - discovery through this cluelessness. Like in some coming - of - age novels, the young characters don't really know what they want at first and the whole story is about them finding their way.
The novel has a great influence on the movie. It provides the basic plot structure. The movie follows the general framework of the novel's story, like the character's growth and development. For instance, the main character's journey from being self - centered to more empathetic is a core part both in the novel and the movie.