Decide on the scope of your search. If you are looking for old cemeteries that may have closed, for the purposes of genealogical research, you will be using one set of references, but if you are looking for current, functional cemeteries for the purposes of finding a burial plot, you will be using other resources. Knowing precisely what you are looking for will help you focus your research.
Contact your local library and speak to a reference librarian. There may be print resources available for your search. Many genealogical collections have indexes listing historical cemeteries and the names of persons buried in them, for instance.
Log on to the Internet and search online phone listings for cemeteries. There are multiple online phone directories (yellowpages.com, for one) that will allow you to filter your search by location as well as by category. This will produce a list of operating cemeteries and associations in California, along with their contact information. There are also genealogical websites that will list closed or family cemeteries and their locations, if you are looking for an old cemetery that might hold family members.
Search online for professional cemetery associations in California. You may be able to find a list of cemeteries that belong to these associations on their websites or you can contact them by phone or mail.