The former vice presidential candidate addressed more than 2,000 supporters at a Republican National Committee rally in Orange County, a conservative stronghold in a state where Republicans hope to make gains this year.
"The momentum is with us but now is not the time to let up, now is not the time to celebrate - not quite yet," Palin told a crowd wearing T-shirts reading "Proud Conservative" and buttons reading "Is it 2012 yet?"
"We can't be thinking that it's over yet and we've got it in the bag. As Yogi would've said, 'It ain't over till it's over,"' she said, referring to New York Yankees great Yogi Berra.
"Soon we'll all be dancing," Palin added.
The event was the culmination of a three-day promotional and political swing for Palin through California - a state where she gets mixed reviews.
A Field Poll released last week found that 58 percent of the state's registered voters hold a negative view of Palin, although she remains quite popular among Republicans. In addition, two-thirds of independent voters would be less inclined to support a candidate endorsed by her.
The state's two most prominent Republican candidates this year - gubernatorial hopeful Meg Whitman and Senate candidate Carly Fiorina - were absent from the rally, citing scheduling conflicts.
Organizers urged the crowd to help out Republican state Assemblyman Van Tran, who attended the event and is challenging Democratic U.S. Rep. Loretta Sanchez for her seat in Orange County.
Palin isn't the only big name politician to visit California in the run-up to the election. Former President Bill Clinton spoke at rallies for gubernatorial candidate Jerry Brown and Sanchez on Friday and will campaign in San Jose and Napa Sunday.
President Barack Obama will visit Los Angeles next week to support Brown and Sen. Barbara Boxer.
Invoking former President Ronald Reagan, Palin told the roaring crowd she wanted a return to principles he espoused: "lower taxes, smaller, smarter government, less overreach and intrusion, strong, unapologetic national defense."
Reagan, she said to a thunderous applause in a Marriott hotel ballroom in Anaheim, understood the little guy.
Wearing a red GOP baseball cap, 76-year old Erwin Vysma said he was thrilled Palin had helped the party swerve conservative after Republicans let spending spiral out of control under Bush.
"She's doing a whale of a job," Vysma said. "She fired up the base and hopefully we'll all come out voting 100 percent, the Republicans, because God knows we need it."
Palin will headline another Republican National Committee rally on Oct. 23 in Orlando, Fla.