When I left California, I left late enough, the end of Nov in 1999, that I simply claimed California as my residency as 1999 and Hawaii 2000 to avoid the hassles of filing two returns. Be aware that California is extremely aggressive about going after income of former residents. In fact it took a US Supreme court case before California stop trying to tax pensions of former residents who had moved to other states.
Despite not spending a day in California in 2000, they sent me a bill for $25k, for stock options I exercised while in Hawaii in 2000 that were accumulated while working in California. They backed off with the help of my former California CPA.
If at all possible cut all ties to California as soon as possible when moving, sell your real estate, get a new drivers license, and certainly don't vote in California. If that isn't possible and you still have business ties in California, you'll probably save some hassle if you do some research ahead of moving.