I'd brushed up with the California Drivers Handbook (which the DMV hands out free) and some sample tests the night before, so I wasn't too worried; driving here is not terribly different to driving in the UK and most of the questions are common-sense safety. As with the UK tests, there's some figures it's worth committing to memory: here they're blood alcohol levels (0.08% for over-21s, 0.01% for 21 and under); some of the parking distances (18 inches or less from the kerb; 15 feet or more from a hydrant); and some of the significant driving distances (indicate from 100 feet or more; enter bike lanes to turn 200 feet or less).
And it paid off: 100% pass. I now have the permit which lets me practice driving accompanied by a license-holder, and I can schedule the driving test which turns it into a full-blown license. The earliest appointment in Walnut Creek was 24th December — too long to wait — but there's another DMV office at Pleasanton which can fit me in on Friday (hooray) and which is has easier roads to test on (hooray again).