Contact the New Mexico Film Office (see Resources). On the web site, click "For Locals" and then "Casting Calls." Visit the site frequently for updates and beware of potential acting scams.
Call a casting agency based in New Mexico. Many agencies represent not only lead actors, but movie extras. These companies --- such as Cherrix Casting in Santa Fe --- have solid relationships with filmmakers and will sometimes book background actors for multiple movies during one season.
Prepare for the hard work of being a movie extra. Working on a film is not always glamorous. Background actors often work shifts longer than 10 hours. A movie extra might have to wait in a room for many hours, walk up and down a street multiple times for the same scene or stand for an extended period of time. Movie directors require background actors to keep quiet on set and follow all instructions given.
Follow professional movie extra etiquette. Arrive earlier than the required call time, bring your driver's license and have wardrobe options (if instructed). Never complain to employees and fellow background extras about fatigue, boredom, hunger or thirst. Have a book, crossword puzzle or MP3 player handy to remedy periods of dullness. Follow all instructions, stay positive and remain respectful, because by behaving like this, a movie extra can keep the door open for future background acting opportunities.
Create a background acting resume. After each of your movie extra experiences, make notations on a "resume" with the film name, release date and director. Expand on each movie extra experience by stating the required "role" and responsibilities and the location of filming, such as Camel Rock Casino or Red Rock State Park. Use this document to land future movie extra roles.