Get head shots taken by a professional head shot photographer. There is a directory of New York City head shot photographers on the Reproductions Web site (see Resource). Prices vary by photographer.
Find casting agencies for extras on the New York 411 Web site (see Resource). Be sure to pay attention to the location because some of the casting agencies are located in Los Angeles. Click on an agency in which you are interested in order to get contact information.
Submit your head shot to each extras casting agency in which you are interested. You can use the mailing address listed. If the casting agency has a Web site, look for any specific information that pertains to submitting your head shot for extra work. Some agencies may even allow you to upload or email your head shot. When you submit your head shot, be sure to include your contact information, height, weight, ethnicity and union status.