Obtain a list of reputable agents in your area from the Screen Actors Guild (SAG) or the Association of Talent Agents. Both of these organizations maintain lists of registered agents, and you can search their websites.
The list will tell you whether or not an agency represents children or has a children's department. Look for agencies that indicate that they represent youth, or are full service. If you are not sure whether or not an agency represents kids, call and ask them (after 4:00 p.m., Wednesday-Friday).
Using the master agent list, make your own list of agents that you would like to have represent your child. A good investment in making these choices is a book called, "The Los Angeles Agent Book," by K.Callan, now in its 8th printing. This book is frequently updated and includes interviews with many of the children's agents in town. This can help you get a feel for which agent is most likely to be a good fit for you and your child.
Take some simple snapshots of your child or have them taken by a professional photographer. A natural, happy appearance in a simple setting is best. Pick your favorite shots and have some copies made, enough for all of the agents on your list.
Create a resume. Use any and all performances. List special skills honestly.
Make sufficient copies of the resume to go to each of the agents on your list.
Draft a short cover letter asking the agent to consider representing your child. Tell them that you will be calling in a few days to see about an appointment. Make a professional-looking copy of the letter to send to each agent on your list.
Mail the letter, photo and resume to the top 20 agents on your list.
Call the agents who received your mailing. Ask for an appointment to come in briefly for an interview. Just assume that you will get one, be very friendly.
Prepare your child for the interview, just as you would prepare her for an audition.
Take your child to each agent interview. Make sure that he or she is well-fed, well-rested and in clean clothing for the interview. And dress neatly yourself! Remember that to the agent, you and the child are a package. A child with a well-dressed, polite and pleasant parent is much more likely to land an agent than one with a harried, loud or ill-mannered parent.