Meeting with an adviser can help you determine what classes your new school requires for your degree, and which of the classes you've already taken will be accepted. Many advisers will map out a schedule of classes the student should take each semester to help them earn their degree.
Most schools have access to a course equivalency guide that list schools by state. Each school then has a list of classes offered. For California, Assist.org is a helpful website to use when comparing course equivalencies. Each college will also list transfer requirements for admission and may have other helpful resources for students.
One of the easiest ways to determine whether a class will transfer is to compare the syllabus of the class you took to the syllabus of the equivalent course at the school to which you are transferring. Generally, if the syllabi cover the same materials, the course will transfer. Many professors are also willing to review the syllabus from your previous school to help you determine whether the class in question will transfer.