Take an aspirin.
Assuming you are one of those people who has no ID, no drivers' license, and somehow is still a legal voter:
The California requirements are here. It's 20 bucks, or free if you're a senior citizen.
Suitable proofs of ID can be found here.
A certified copy of your birth certificate is 15 bucks.
If this is too onerous, you don't really want to vote that badly in the first place.