Becoming a PG is a significant professional accomplishment and there are many rewards:
You can make a significantly higher salary.
You can work on, and have greater responsibility for, a greater variety of projects.
It is easier to change jobs or start your own business in geologic consulting.
Appropriate education: sufficient units in geology overall and within specified topics. The educational requirements are specified here (see highlighted parts of pages 7 - 10).
Sufficient and relevant work experience under the supervision of licensed professional geologists.
Note that work experience does not start to accumulate until your educational background meets the educational conditions. This means: Study geology now! You'll enjoy it, anyway 😃
Passing the California state Professional Geologist Exams.