Alliterative List

Sometimes a character doling out Rule Number One has a snappy list of a few words, each beginning with the same letter. He can therefore refer to the rules as "the five M's", or whatever. For added comedy, they may not exactly start with the same letter.

Examples:

Anime and Manga

 * The first duel theme in Revolutionary Girl Utena famously begins with "When Where Who Which" (also the song's name). Utena being Utena, the exclusion of "Why" turns out to be significant to understanding what the duels are and how they actually work.

Film

 * Alec Baldwin in The Movie version of Glengarry Glen Ross has the ABCs: Always Be Closing.
 * Parodied on Saturday Night Live when Baldwin appeared in a Christmas Elves sketch: "Always Be Cobbling."
 * Dodgeball has the Five Ds of Dodgeball: Dodge, Duck, Dip, Dive and Dodge.

Professional Wrestling

 * Kurt Angle had the Three I's: Integrity, Intensity and Intelligence.

Video Games

 * Four X games.

Western Animation
"Chief Wiggum: Now, just follow a little formula called PB & J. Peer at the monitor. Be judgmental. And jot it down. One way to remember that is A-B-C. Always Be Considering PB & J. But the single most important rule is the four As. Always Act According to A-B-C."
 * The Simpsons, "To Surveil, With Love": Chief Wiggum is explaining the duties to some civilan volunteers.

Web Animation

 * In the Strong Bad E-mail "pizzazz", Strong Bad says that he's cool because of the "three G's": Gumption; Gum, like, chew gum; and Gar... gle. Minty gargle.

Real Life

 * The Ur Example is possibly the three R's of education: Reading, 'Riting and 'Rithmatic.
 * Ian Stewart and Jack Cohen, in their books on evolution and xenobiology, refer to "universals", which evolved many times to solve the same problem, and which we might expect alien lifeforms to also evolve, and "parochials", which only evolved once, however important they might seem to us. The most significant universals are the four F's: Fur, Flight, Fotosynthesis and F... sexual reproduction.
 * The three R's of waste management: Reduce, Reuse, Recycle.
 * The four D's of dyslexia: Defining, Deciphering, Diagnosis and Dealing.
 * In certain Christian denominations, it's extremely common for pastors to organize their sermons in this way.
 * Answers in Genesis has what it calls "The Seven C's of History".
 * Slip, Slop, Slap: the Australian mantra for sun protection from a highly successful PSA campaign. (That's slip on a shirt, slop on sunscreen and slap on a hat). In recent years, they have added Slide (on sunglasses) to the list, although this hasn't quite permeated the public consciousness the way Slip, Slop, Slap did.
 * The United Kingdom goes for the far less catchy "Wrap, Splat, Hat".
 * Clunk-click, every trip - for the UK safety agency Ro SPA's 1970s seatbelt campaign.
 * Who? What? Where? When? Why? How? The five dubyas (and an H) of journalism.
 * The old science show Johnny Ball Reveals All had "Who, What, Why, Where, When?" as part of the theme tune enthusing about curiosity.
 * There's the Four Fs of evolutionary biology: fighting, fleeing, feeding, and procreation.