First off, skip the warm weather clothing; you're not moving to Southern California. The weather here is routinely chilly, damp and gray. That doesn't stop people from having fun, but it does mean you'll need to pack one of those windproof umbrellas. Spoiler alert: They don't work.
Also, the rental market is rough. R-U-F-F. Plan well in advance to start your search, and don't expect to find something before several months have passed. Make decisions quickly when an opportunity opens up, or you'll miss it. First and last month's rent, security deposit and your first born are typical requests. Also, these houses and one-bedroom apartments are historic and character filled. So bugs, chipping paint and questionable wiring are fairly standard. Embrace the chaos. And that goes for every day life too. This is a real cross section of humanity, so keep your sense of humor on command. Finally, parking is nearly nonexistent. Moving with a big ole truck (to an apt for rent with no elevator and narrow stairwells) will give you a headache from which you may never recover. Start downsizing now.
The Civic Center neighborhood takes up fewer than five square blocks, so there aren't major differences between one end and another, but here are some tips for finding the perfect location.
North: You'll find the Asian Art Museum, a smattering of restaurants and bars and the first edges of the Tenderloin in this area. It can be a bit run down closer to the edges, but it's quieter than other spots.
South: The arrow tip includes a hippier/hipstery vibe as you verge into Hayes Valley. There are also good restaurants, and it's a straight shot to Golden Gate Park.
East: You can argue that Market Street fully encompasses the east side. BART, MUNI, the UN Plaza and a few European style hostels are readily available. This is a busy, busy area, so if you love a bustling metropolis, park it here.
West: It's all about Van Ness Avenue in the west. Oodles of restaurants, shops, cinemas, art galleries, a weird classic car collection and bars, bars, bars. Van Ness is also the 101, so if you need to get somewhere in a hurry, well, you still won't. Traffic is insane here, but you're still at the front of the line.
Moving from anywhere to the city is an adjustment. Life is just different in San Francisco. It's the biggest little city only seven miles across but it's got a lot of personality packed into the place. People here are active; they're into healthy living and they love to walk. Seriously, your glutes will get some serious exercise here, between the long blocks and high hills! Sure, there's plenty of public transportation, including the MUNI, BART, Caltrain and trolleys, but if the destination is within a mile, you'll probably walk or bike there.
Food is big business here! There are just as many folks who love to cook at home as eat out nightly. Cost of living is fairly outrageous, so if you need to scale back, you can do so by hitting farmers' markets and mom-and-pop shops (of which there are oodles) and make a culinary masterpiece at home.
If you live here, expect to sample a little of everything, from the symphony and opera house to the library. All these gorgeous buildings should be investigated, and people will talk with you about them, at length. At night, you're spoiled for choice. Van Ness has a stop for every taste. Life is lived above the speed limit, but you'll learn to pause and savor every exhilarating moment when you live here.