Hire a professional photographer--one who specializes in the entertainment industry--to take headshots, which will be your calling card for acting jobs. Typically, your acting resume will be printed on the flip side. Pick up a free copy of LA Weekly or check backstage.com for listings of photographers and resume printers.
Get some training. Acting is a craft with many different styles and skill sets, and the best actors are always learning something new to add to their repertoires. In Los Angeles, acting instruction runs the gamut from small storefront studios with classes taught by a single teacher to full-fledged university programs at institutions such as USC, UCLA and the California Institute of the Arts. For the beginning student, community education classes in acting at Los Angeles City College or the UCLA Extension are an excellent choice. Los Angeles is also the home of several well-known acting schools, including Stella Adler, Sanford Meisner and Lee Strasberg.
Audition for roles. Now that you have your headshots and have taken some classes, you're ready to put yourself out there. Actors in Los Angeles find out about open auditions from a number of online sources such as Craigslist, Backstage and Infolist and the Hollywood trade papers Daily Variety and the Hollywood Reporter. You will need a phone number with voice mail, as well as an email address and access to a computer, to find out about jobs and callbacks.
Build your reel. This is the DVD or online video version of your roles in film, TV series and commercials, which casting directors will want to see. You will find lists of videographers and film editors who specialize in actor reels in the same places that list headshot photographers.
Self-promote yourself to casting directors. A casting director has the power to hire you for an acting job in Los Angeles. Online casting resources such as actingland.com, where all casting directors looking for actors are listed, are a good bet. Also listed there are the showcases that casting directors attend, which is another way for an actor to get noticed in Los Angeles.
Find an agent (eventually). You won't need this when you are just starting out. Once you start working with other actors, ask them who the good agents are. Sites such as actingland.com and backstage.com have lists of talent agents, as does the Hollywood Creative Directory. Sites such as the Internet Movie Database (imdb.com) list working actors' agents. Call them and ask what they will need to consider representing you. Often it will be your headshot, resume and reel. The best way by far to get an agent is from a personal referral, and it may take you some time as a new actor in Los Angeles to build up the network for this.
Network. Los Angeles is a company town. Virtually everybody who lives in Los Angeles knows someone working in the business, and on any given night there are numerous events, screenings, classes, panels, signings, etc., which are low-cost or free and open to the public. The industry is collaborative, and aspiring actors will find writers, directors, producers as well as other actors and everyone else involved in film and television at these events. Calendar listings can be found in the Hollywood trade papers as well as the Los Angeles Times and sites such as experienceLA.com.