This never turned up yesterday when I used the menu to look at Today's Posts.
The most important thing is soil drainage. You already understand this from growing orchids, so you're ahead of the curve. Most succulents in growth should stay moist for 5-7 days after a watering, then go just dry before the next watering. Some require a dry dormancy, and others don't.
It doesn't much matter what you grow in so long as it drains rapidly. Succulentists tend to use mixtures of [potting soil] + [gravel and/or perlite and/or pumice and/or volcanic cinders and/or LECA] +/- local soil. The minority (including me) do not like to use organic matter in our mixes. Mixtures with peat or potting soil deteriorate and become black, rotten mush in 2-3 years, so plants in such media must be repotted frequently. Those of us avoiding organic components can leave our plants in the pots until they outgrow the pots. Your Bay Area soils are excellent for succulents, and if you could get some of that, I think it would be easiest.
If you use mixes without real soil, you will need to fertilize regularly during the growing season. Most succulents appreciate heavy fertilizing. Warnings about not overfeeding come from low-light parts of the world. With your higher light intensities you can feed heavily.
In general it is better to underpot rather than overpot, unless it is a plant that likes a lot of water during its growing season. A lot of succulentists like to use very shallow tray-like pots, much as for bonsai. Take care they do not dry out too fast, or you will be watering your succulents a lot.
Second most important is light. There are not many shade succulents. There are a few that can be grown on windowsills or indoors under lights, but most need outdoor light. Providing enough light for commonly-grown succulents in families Agavaceae, Aizoaceae, Aloaceae, Cactaceae, Crassulaceae and Euphorbiaceae indoors is quite difficult, even with modern lighting systems. Haworthias and Gasterias, and miniature Aloes, are some that can do well on windowsills, as well as some of the Euphorbias and milkweeds known as stapeliads (after genus Stapelia) that grow as understory plants.
Your microclimate makes a huge difference. Most cacti aren't happy without more heat than, say, the Sunset or Richmond districts in San Francisco get. Other succulents come from high altitude, or cooler coastal areas, and do very well in such places. So you need to know something about the plants. Growers can modify the surroundings to provide more heat.
A brilliant example of this is the
cactus garden at Lotusland in Montecito, near Santa Barbara, California. The coastal Santa Barbara climate is too cool for most cacti. The designer Eric Nagelman used small shards of black slate for mulch; this absorbs heat from the sun and renders the garden warm enough to grow lots of cacti.
Most of the world's succulents are summer-rainfall, winter-dry plants. Your winters are too wet to keep a lot of these outside, so people resort to greenhouses or twice yearly heavy lifting.
But - Your winter-rainfall, summer-dry-and-hot climate matches that of succulent-rich areas of southwestern Africa and western Chile and Perú, and a lot of the succulents from there can naturalize in the Bay Area. Imagine, not needing to water your plants all summer! The ice plant relatives from these areas (family Aizoaceae) are spectacular in bloom.
Many higher-altitude or cooler-climate succulents in the Crassulaceae also do well outside in the Bay Area, because they are accustomed to cool nights with dew for most of the year. This includes genera like Crassula, Echeveria, Graptopetalum, Pachyphytum, Sedum and Villadia. You like miniature orchids; a huge number of these species are miniatures that look great, and flower, in thimble-sized pots.
The epiphytic cacti, including the ones known as Epiphyllum hybrids, are easy to grow in the Bay area so long as they receive no frost. Epiphyllum hybrid flowers are beyond amazing.
There are a number of cactus and succulent societies in the Bay area. You can find a listing
here.
I forgot about spider mites, mealy bugs and scale. The majority of commercial plants you buy arrive with these. Outside it's not much of a problem, but inside root mealies can kill plants before you know what hit you. I put imidacloprid containing lawn granules into the soil mixes of all my plants susceptible to mealy bugs (cacti, milkweeds) and any plants that arrive from California. I keep a close eye for spider mites during warm and dry seasons.
Cacti-Succulents Basics
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