If you have a family member — a child, a spouse, etc. — whom you want to write completely (or partially) out of your will, you basically have two options.
Option one is that you specifically exclude (or limit) that person in your will, and include a "no contest" clause which provides for that person to receive nothing (or next to nothing) if the will is upheld in probate court.
Option two, and the better option, is to use a revocable living trust. A living trust is much harder to challenge in court than a will, and trust contests almost always fail.
Consider this: a will, by its very nature, is presumed to be invalid right off the bat unless and until the probate court determines it to be valid. A living trust, on the other hand, is presumed to be valid unless and until the probate court determines that it's invalid. California public policy favors the validity and enforceability of a trust created for any purpose that is not illegal nor against some other public policy.