Jump online and go to the Tennessee Film, Entertainment, and Music Commission website. Industry made movies and many locally produced films cooperate with this organization on matters of permits, tax incentives and casting. The Commission's website has constant updates and requests for film extras across the state. Most requests will have available "open casting calls" (large auditions for Tennessee extras), or specific contact information for appointment auditions. If nothing is currently available on this site, then check out your local online newspaper. Casting agencies, local filmmakers and Hollywood productions often advertise in the "Jobs" section for open casting calls.
Learn all you can about the film for which you are auditioning. By gearing your resume and clothing to the film's genre, the chances of landing the job skyrocket. Search online, call the Tennessee Film Commission or simply ask around the area to discover the genre of the film in question. Then add any "special skills" you might have to your resume that relate to that genre (for example, if the genre is "western", state that you can ride a horse). Also, wear clothing that fits the genre. If the film is about farmers in the Great Depression, wear overalls and work boots. If you can't find any information on the film, then simply dress in presentable attire, such as casual dress pants and a collared shirt. Avoid flashy or label covered clothing. Solid dark colors are usually best.
Show up to the audition prepared and smiling. With a headshot (a professional or personal head photo) and resume in hand, the filmmakers and/or casting agent will take you seriously. Your proper appearance will help them to easily "see" you in the role, and an enthusiastic attitude will make filmmakers want to hire you. It's true what they say about the film business -- fun people work more than crabby people.
Work for what you want on set. Many famous filmmakers and actors began as film extras. Extra work can lead to a greater career in the film medium, but it's up to you to make this possible. As an extra on set, you'll have plenty of free time between takes. Use this free time.
If you are interested in being a filmmaker, find a good out of the way spot and observe the process. If you are interested in being an actor, network with other actors on more available and/or potentially available film projects in the area.
However, if you are not interested in furthering your career in film medium, then simply enjoy the fact that you will now be immortalized in cinema.