i passed my first time.
always look both ways coming out of a parking lot, stop sign or stop light. and make it obvious that you're looking.
when you get onto a street, don't accelerate too fast (even though you may not be speeding, they'll still mark you down for it.) i got onto a street that had a 40mph limit, and i accelerated to 35 pretty quick to get up to speed with the flow of traffic and was marked down for it, so take it easy there.
make sure you know your car before you take the test. you need to know where your brights, headlights, parking lights, windshield wipers (front and rear), four way blinkers, turn signals, side mirror controls and defrosters are.
oh, and this is kind of a no brainer...but don't flip anyone off.
and don't make any comments about stupid drivers (which in california, you're sure to encounter) because any sign of road rage is an automatic failure. one of my friends failed his driving test because someone cut him off and he flipped the guy the bird. automatic fail.
good luck! let us know how it went when you get back.