If you are just looking for places to practice in the South Bay (which I will assume includes the Southern Peninsula region), I might suggest a few, in no particular order:
1. Stanford -- The architecture is beautiful and takes light well, there is often a lot of space between buildings to let in natural light, there are a variety of art installations to practice, the towers (Hoover tower and the smaller White Plaza clock tower) are good practice for working with tall verticals, and due to its status as a tourist destination, there is very little fear of cameras.
2. Berkeley -- (North Bay, admittedly) Much of the same holds for Berkeley, with a greater number of hipsters and the added benefit that there is a very nice botanic garden to practice on above the campus. The Berkeley Pier is a subject which clallenges one to frame it in a new way, and the yacht club is the largest in the Bay Area (iirc), making for a number of interesting boats going in and out.
3. Palo Alto Baylands -- If you want to try bird photography, easy subjects may be found at the Palo Alto Baylands, accessible either from the end of Embarcadero Road, along the frontage road between San Antonio and Embarcadero, or at the end of Runnymede ave in East Palo Alto. All three areas are popular with birdwatchers, and are good places to see ducks, egrets, shorebirds, and pelicans. The endangered Clapper Rail lives in that environment, and the best place to see it is in 'Rail Alley' at the Embracadero end.
4. Santa Cruz -- Pick up a book of coastal/redwood photgraphs, and try to take shots with the same feel--a good day trip, Santa Cruz is a typical coastal town in many ways (Half Moon Bay, to the North, is more attractive to my eyes--go there around the pumpkin season especially). There is a lighthouse, UC Santa Cruz, acres of Redwoods, and butterflies coat the trees in season at Natural Bridges State Beach.
5. Highway 1 -- This affords a variety of coastal highway scenes, from the rustic to the semi-industrial to the more typically scenic, and heading North, the Devil's slide area is a butterfly preserve (if I remember correctly). Highway 1 has been photgraphed quite a bit, so you can get ideas of what look for, and then practice similar shots (the winding road with lone juniper, iceplant with hills and oceanscape, etc.)
6. Highway 9 -- Heading up into the redwoods, there are a variety of small towns and conservation areas that make for decent photography. Big Basin and Henry Cowell are both State Parks with nice redwoods. Plan on being there in interesting weather to capture the feel of the redwoods in the morning fog or look for fallen logs to make strong geometric compositions. If you want to head significantly further south, Mt. Madonna is an ideal climate for mushrooms, in my experience.
7. Monterrey -- Much the same as Santa Cruz, though an hour or so South along Highway 1, you have the added attractions of Cannery Row and the aquarium. It features in a lot of phots, so you can get an idea of what to look for and then practice those shots or work off the theme.
8. Skyline -- Skyline Blvd, at the top of the Santa Cruz mountains, has a variety of scenic vistas as well as the opportunity (if you and the subjects are up to it) of photographing all the sport bikers that make it their constant weekend haunt (they alol meet at one particular intersection, I forget which). If want to try making geometric compositions out of Christmas tree farms, that is a good place to find them.
9. Niles Canyon -- Niles canyon, which begins in Fremont, has a variety of very odd features. The river is occassionally scenic (fog helps, but it floods and gets murky quite regularly), but the neat thing is the excursion train, which could be fun practice due to the antique cars and the fact that the operators plant wildflowers which should be blooming now (or perhaps they are past, I am currently in Toronto). I think the old test reactors are quite attractive, faded aluminium against the green hills, but they may not be the wisest photgraphic subjects in the current climate.
If you looking for interesting sites, dig up the old TV series 'Bay Area Backroads,' or its sucessor 'Mac and Mutley,' or a book by the same guy who did that series. He visited all kinds of weird areas in the Greater Bay Area. There is also something to be said for just practicing on getting the typical Golden Gate Bridge shot, in order to imporve your composition on a known commodity.
I hope that is somewaht helpful.
