Stephen Dorff and Elle Fanning spent a lot of time together prior to the shoot in order to build the father-daughter relationship their characters have. For example, Dorff sometimes picked Fanning up after school.
A number of the dialogs were improvised by the actors, notably the things said by Sammy (Chris Pontius) to Cleo (Elle Fanning). This was done in order to provoke genuine surprise from Fanning. Pontius, in fact, was specifically chosen for his improvisation skills, as well as his good rapport with children.
Executive producer Fred Roos suggested the casting of Elle Fanning. Her performance in El curioso caso de Benjamin Button (2008) impressed Roos. Sofia Coppola was initially reluctant however, believing Fanning to be a typical, professional Hollywood child actress, but agreed to meet her, and was won over.
There is no dialogue until 15:02 into the film.