Night flying is good flying, and in the Bay Area it's fantastic (I fly
out of University Airport near Sacramento). More than once I've flown
over the Bay with a full moon and wished I had high-speed b&w film in
an SLR to capture the view.

Consider buying an LED headlamp in addition to a more traditional
flashlight. I find the headlamp great for preflight inspection,
cockpit arranging before starting, and postflight matters.

Start by waiting for good weather and a forecast of good weather
through the evening--no storms or fog. Pay particular attention to
the temp/dew point spread. Start doing takeoffs and full stop
landings before it gets dark, and continue until it is fully dark or
you're tired or uncomfortable. Bring an experienced pilot or
instructor as pax if you are not at all comfortable starting this way.
That's enough for one outing.

Do this again within a week or two. This time you should be more at
ease, though perhaps not fully so. That's OK. Do a short night hop
to a nearby airport that you have done many times in the daytime, for
instance, San Carlos to Palo Alto or Reid-Hillview. Bring a GPS that
you know completely how to use, it can really help at night. Don't
let some weenie tell you that real pilots don't depend on GPS. You
don't want to depend on it, but you do want it as a help.

Once you've flown to 2 or 3 airports in the Bay Area at night, pick an
airport outside the Bay Area, let's say Sacramento Executive. Fly
there once in the day if you haven't done so before. Be damn sure you
have a waypoint or two that is easy to spot and that you know what
altitude you must be at to avoid the BA hills. You might fly there in
the late afternoon, get dinner in the restaurant there, then fly back
at night. That gives you a goal and a feeling of accomplishment. Use
NorCal approach and ask for flight following.

Half Moon Bay is another nice destination. The winter is good to fly
there 'cause the coast doesn't have so much fog. Auburn in the
foothills is good too, it has a good cafe (check the closing time).

Northern California is an amazing place to fly, day *and* night. Good
on you for wanting to become better at night flying. So many pilots
avoid exploring their personal envelope...they're missing a lot of
great flying.
--
No great intellectual thing was ever done by great effort.
Theodore Roosevelt