Becoming a private investigator begins with researching the qualifications related to the state in which you live. Most states have a professional licensing board that regulates the profession. In Georgia, for example, you can go to:
http://sos.georgia.gov/plb/detective/
and research the requirments. I am going to give a synopsis here for Georgia as an example.
First, you must decide if you want to open your own agency or if you want to work for an existing agency. Opening your own agency requires two years of full time experience or a four year degree in criminal justice, passing the state exam, and obtaining insurance or bonding. The next step is to get a local business license and look for prospective clients.
If you want to work for an existing agency, start by looking for classes approved by the Georgia Board of Professional Private Investigators and Security Agencies. Once you find them you can sign up and then apply for a student membership in one - or both - of the state professional organizations (www.gappi.org or www.ispag.org). Attend the classes, attend the meetings of the organization(s), and let everyone know that you want nothing better than to be a licensed private investigator. You should have no trouble entering the field if you are aggressive, passionate, and determined.
Good luck!
Go to:
http://www.safeharborinvestigations.com
for more information.