Get a degree or training from a respected theatre college or local acting school. If neither is available, find any acting training that is available in your area. Contact your community college for a catalogue of acting classes. Join a local theatre group. Volunteer for any acting position available. Agents insist on seeing past and continuous training for any actor in which they express interest.
Educate yourself on the different agency types. Agencies who cover acting talent for film, television and theatre are known as "across the board" agencies. Agents in these agencies specialize. You will rarely have the same agent for television that you have for theatre. It is important to know which facet of the industry you want representation in, and to focus your attention on that area. Never respond to an agent who asks: "What do you do best?" by replying, "I can do everything." Know your own talent and be specific.
Go to a photographer located in the market in which you want to work, and one who is experienced in taking headshots. Agents look at a headshot for five seconds before making a decision to look at the resume on the back. If you are looking for a commercial or a television agent, take a headshot that shows good teeth and a dazzling smile. Attracting a film agent means showing a face with depth of character. Projecting a story in a headshot will grab the attention of a "legit" (theatrical) agent.
Build your resume with concise and honest information. Be sure it has all your necessary contact information. Include any "extra" work you have done, but not more than five appearances. Education is vital, and continuing education is a must. Special skills are especially helpful to television agents. If you ride a horse, that may be the skill that will get you an audition for a western-themed commercial or television pilot. Be sure the resume is the same size as the headshot and is stapled to the headshot in all four corners.
Know your industry. Stay informed by reading "Backstage" (either East or West) and the "Ross Reports," which give auditioning advice and updates on who's who in the agency business. Agents move agencies frequently and these industry publications will help keep you up-to-date. They also list casting calls.
Take your acting jobs seriously. Every acting job is another addition to your resume and an education as well. Offer your services to a local company for their advertising campaign. Maybe you won't get paid, but it gives you training to list on your resume. Invite local agents to watch your performances and follow up with a hand-written note of thanks if they do attend.
Make a DVD of your acting appearances. Keep it short -- three minutes in total. Send it to agents with a short cover letter and a headshot/resume. Do not call for follow up. Keep sending headshots every six weeks with updates on your career, or invitations to showcases.