During the game of "Suck and Blow" the cast was unable to sustain the breath to make a real credit card pass from mouth to mouth; a prop card made of cardboard was substituted that still did not work. Holes were drilled into it to make it easier, and when this failed also, the whole cast's lips were heavily coated in chapstick to force the card to stick.
Alicia Silverstone did not know how to correctly pronounce "Haitians" in the classroom scene. Amy Heckerling told the crew not to correct her because she liked it so much and wanted it to be in the film.
One of the promotional items distributed to tie-in with the film was a booklet called How to Speak Cluelessly; in it was a lexicon of many of the invented terms used for the Clueless world (some of which became part of real teen lingo at the time). An example: a Baldwin is a very handsome male, as in the famous sibling actors.
Plot, Characters, Themes and Values are all based on Jane Austen's novel [Emma]. Amy Heckerling was asked by Paramount to write a film for teenagers, and she instantly remembered the novel she read as a teenager.
Although Paul Rudd's character, Josh, is in college and is older than the other characters who are still in high school, Stacey Dash, who plays the best friend Dionne, is actually 3 years older than Paul Rudd.
In the MTV Movie Awards for the year following the release of Clueless, the geriatric cast of The Golden Girls (1985) did a spoof on some of the high points of the film, most notably the "balls flying at my face" scene at gym class.
Although with many obvious modernizations and adaptations having been made, "Clueless" actually does still dovetail pretty closely to the original plot and central set of characters found in Austen's "Emma". In terms of the cast, for instance: Cher is Emma, Josh is Mr Knightley, Tai is Harriet Smith, Elton is Mr Elton, Travis is Robert Martin, Christian is a loose and much more sympathetic version of Frank Churchill and Dionne could feasibly be Mrs Weston (although it is also possible, given that Cher attempts to matchmake the two of them, that Mr Hall and Miss Geist could also be Mr and Mrs Weston, who, likewise, Emma claims to have matched.).
Cher's last name is given as Horowitz, but shown on her report card as Hamilton. This may be an in-joke, as director Amy Heckerling's previously directed Fast Times at Ridgemont High (1982), which featured a Stacey Hamilton.
Scenes were included in the trailer that were not in the film. Among them is one in which Cher and Dionne are in the girl's bathroom primping when Amber walks in on them. Noting her appearance, Cher quips, Did I miss something? Is big hair back?
Cher's "Haitians" speech in debate class was initially a full minute longer; it was used in its entirety as the first half of an original theatrical trailer. It was cut for the final film but featured additional comparisons to her garden party including a rant on "mismatched chairs which was totally icky".
A promo was filmed for MTV that showed Dionne and Cher ordering food at a diner. Their waitress was their moonlighting lesbian P.E. teacher Miss Stoger (Julie Brown). In it they get freaked out by the idea of brine in their ceasar salad, and instead just order lemon wedges to suck on.
The high school where the students attend is "Bronson Alcott High School". Bronson Alcott was a nineteenth-century Transcendentalist writer best known for starting an ultimately unsuccessful Utopian community called "Fruitlands" and for being the father of "Little Women" author Louisa May Alcott. At one time, Amy Heckerling dated Bronson Pinchot (whose middle name is Alcott, after the author). "Bronson Alcott" is also the name of the prep school in Nat Hentoff's 1976 novel 'This School is Driving Me Crazy', where the protagonist's father is headmaster.
Alicia Silverstone and Paul Rudd would both go on to portray superheroes, from DC and Marvel universe respectively. Silverstone would portray Batgirl in the movie Batman and Robin (1997) and Rudd would portray Scott Lang in Ant Man (2015).
The trivia items below may give away important plot points.
In the scene where Cher is packing for her father, and is surprised by Christian's call, he is at a museum. The painting behind him is of two men affectionately in an embrace - another foreshadow of his sexuality.
The films that Christian watches on video with Cher - Some Like It Hot (1959) and Spartacus (1960) provide clues to his sexual orientation. The first movie deals with cross-dressing men (who are escaping from a mob hit). The second includes the famous scene where a Roman master (Laurence Olivier) tries to seduce his male servant (Tony Curtis).
When Christian first appears at the class, Cher has new hopes for high school boys. But as the shot pans from her gaze to him in the doorway, just over his left shoulder on the wall in the classroom is a cut out headline from the newspaper which reads On the Road to Nowhere.
The scene where Cher wanders around and realizes her true feelings for Josh as fountains erupt is borrowed from Gigi (1958), where Gaston does the same thing. The music playing when Cher stands at the top of the stairs in her white dress before her date with Christian is taken from the same movie. Gigi, incidentally, wears a white dress both times that particular theme is played.