They made about 20 puppets for every character, each one of them taking months to make. And they replace the mouths between shots.
The garden scene, the mice circus, the theatre, the Other Mother transforming and the other world disintegrating... they're not CGI. They're done with stop-motion. The mice are animated by replacement parts; every single movement needs an entirely new, sculpted mouse figure.
The characters' hairs have to be "injected" one by one.
The costumes are made by an impossibly patient lady with needles as small as human hairs. That lady's name is Althea Crome, and her part in the making of the film is detailed in this video.
Dye Hard: Coraline herself; an old family photo reveals that her real hair colour is a medium-brown, close to her dad's colour.
Fake Nationality: Ian Mcshane as Mr Bobinsky - Bobinsky is Russian while Mcshane is British.
Network to the Rescue: Initially, no studio showed interest in the film. Then producer Bill Mechanic (who also believed in James Cameron and Titanic at Fox) showed interest and jumped on as a financier, which got the film made and a distributor in Universal. The movie became a Sleeper Hit, director Henry Selick got a deal at Pixar and the animation studio now works full-time with Universal.
The Red Stapler: The Detroit Zoo fountain snowglobe was eventually produced as an actual zoo souvenir after the film was released.
Sleeper Hit: When the film came out, stop-motion animation was considered dead and the film was expected to die a quick death at the box office against Pink Panther 2 and the My Bloody Valentine 3D. After a better than expected opening, the film kept on going until finally becoming the highest-grossing stop-motion animated film of all-time.
Star-Making Role: For Laika Animation themselves, whose success with the film lead to closing their CG feature division entirely, to focus entirely on their stop motion division.
What Could Have Been: The movie was originally planned as a musical with 10 songs written by They Might Be Giants, but this idea was discarded in favor of a more conventional movie, although one of their songs (the Other Father's number) does remain in the film, and the band has said they will release the other songs written for the movie on other projects ("Careful What You Pack", for example, wound up on their 2007 album The Else).
At one point, there were plans to use two different animation techniques for the film: stop motion for the real world, and CGI for the Other world. However, when tests of this approach were attempted, it was found that the stop motion looked much more visually interesting than the CG, making the world Coraline left seem much more interesting than the world she entered. So they tried a switch, with CG for the real world and stop motion for the Other world, but this didn't look right either, so they settled with an all-stop mo technique.
There was a lot of discussion about the famous Other Spink and Other Forcible performance, specifically exactly how much they could get away with. Selick said he convinced the company to let it slide because Other Forcible was not only covering her naughty bits, but was also spoofing a socially acceptable, famous painting.
The movie's production took five years, at the rate of roughly three seconds a day.
It is the first stop-motion movie to be produced in 3D. As the side-by-side camera rig commonly used in live-action shoots cannot fit into the miniature sets, not to mention unable to create the desired results, the camera crew solved this by building a camera rig that slightly move the camera sideways after each take and take a second picture, resulting in the 3D effect seen in the movie.
Most of the non-stop-motion effects are either hand-drawn or shot in live action, with as few CG effects as possible.
The character Wybie Lovat was not in the original book, and was added following producer Bill Mechanic's suggestion. The decision is approved by Neil Gaiman.
Throw It In: The scene with Other Spink and Other Forcible was originally meant to have a song written by They Might Be Giants (as was a lot of the rest of the film, but that's another matter). After hearing the placeholder song the writers had come up with, John and John said it was good enough and there was no reason to replace it.