I'm not familiar with California waters as I'm a Minnesota guy but I'm an avid angler who's fished many bodies of water in the U.S. and Carribean which has allowed me to fine tune my tactics. Majors, minors,lunar phases (lunar impacts predatory fish like musky, bass and pike more) and seasons all play a roll in catching fish but air pressure also plays a major role in finding fish. If the air pressure is not right the fish lay on the bottom and are reluctant to bite. A good rule of thumb is stable pressure, gradual increase/drop in pressure or a stable dramitic high (30+)/low (28 or less) is ideal for fishing. If the air pressure is on a dramitic rise or drop avoid fishing.
Now on to species, tackle and location. Are you just fishing in general or are you targeting a specific species? If you're looking for bass you are in luck, I fish bass tourneys and leagues every year and have gotten pretty handy pulling out picture worthy fish on bad days. Let me know what you target or would like to target and what you typically use for lures/bait/tactics. I have a few pointers for you to try. If you like to fish particular lakes, let me know which lakes. I'll review the lake maps and let you know spots I would single out. Lastly, are you shore fishing or casting from a boat?
Best of luck,
Nate