It starts off by breaking the 4th wall. Various characters use their forefinger to draw a square (the "fourth wall") no less than three times in the film. There are also lots of self-conscious screenwriting terms and phrases like "Every story needs a hero", "What our story needs is conflict", "It is metaphor", etc.
Here are the film references I spotted starting from the beginning:
Cat Ballou/Blazing Saddles: musicians singing story are visible to us and to the players in the film.
Fear and Loathing in Las Vegas: when Rango is flung against a windscreen
Big Lebowski: Chameleon/rock creature sounds like Jesus Quintana ("dios mio!")
Sergio Leone's "No Name" Trilogy:
(Fistful of Dollars, For a Few Dollars More & GB&U)
Spirit of the West = The "Man with No Name" i.e. Clint Eastwood
Rattlesnake Jake = Lee van Cleef
Good, Bad and Ugly (GBandU) = bird's cry used to bleep swear word
Once Upon a Time in the West = squeaky windmill from opening sequence
Django: the gattling gun in Rattlesnake Jake's tail
Star Wars IV: visual echoes of Mos Eisley Cantina in the Saloon
ALSO the fight in canyon is like final Death Star canyon sequence
|Jabba the Hut (Star Wars IV) & Buford the Barkeep (Rango)|
Jurassic Park: dinosaur/bird uncovers someone on the toilet
Chinatown: Ned "The Mayor" Beatty mimics John Huston's villain AND
Chinatown: theme of water in desert, drowned man in desert, etc...
The Man Who Shot Liberty Valance: hero is a fraud
Apocalypse Now: bats/helicopters fly out to Wagner's "Ride of the Valkyries"
There are also references to Ghostbusters, Planet of the Apes and Deliverance. (See the comments below... and add your own!)