How do you do San Francisco in just one day?  First, plan ahead and mark down the most important places you want to see, setting reasonable expectations of course.  Since I love photography, I found this website/blog that tells you the exact spots to go to for the best photo angles.  You can also go with one of the many tours available and reviewed on Trip Advisor.  I had considered taking the walking tour of the victorian mansions or an all day walking tour that used public transportation to get to the different neighborhoods.  Another impromptu way we found to see the city was to befriend a nice local at a popular bar who insists on driving you around and showing the off-the-beaten-path neighborhoods, like Billionaire's Row on Broadway Street and Hayes Valley boutique shopping, in addition to introducing you to neighborhood nighttime hot spots.

Staying in Union Square, it is easy to hop the Powell-Hyde cable car to Hyde & Lombard - the first stop on this tour: Lombard Street, famous for being the most crooked street in the world.
View from the Top
View from the Bottom
Walk down Hyde Street to the cable car turnaround, enjoying views of the Golden Gate Bridge and Alcatraz along the way.
Turn left if you're in the mood for chocolate and visit Ghirardelli Square where you can have a sweet snack at their chocolate cafe, watch chocolate being made, and pick up a free sample chocolate square in the store.
Go back toward Hyde Street and head down a block to the water, passing by The Cannery shopping center where you can opt to take a tour aboard a vintage firetruck.  Continue on to Fisherman's Wharf, following the delicious smell of bread baking to the Boudin Bakery, where you can grab a loaf of my favorite sourdough bread.
Continue down the street, spying San Francisco's large collection of preserved street cars from around the world still in operation along the F Line.  Then make a stop at Pier 39 to observe one of San Francisco's favorite attractions - the barking sea lions lounging on floating docks.  You can also catch a boat to Alcatraz here.
We opted to head up Stockton Street and stumbled upon a beautiful city park and church in the North Beach neighborhood. From this point, we had to grab some wheels to see the last items on the checklist.
First on the driving itinerary was Alamo Square to spot the famous Painted Ladies - Victorian homes built in the 1890s that are painted in vivid colors to enhance their architectural details.  Many may recognize these six homes on Steiner Street from the opening credits of T.V. sitcom "Full House."  From the top of the park hill, you can catch a great view of the city skyline.
From Alamo Square, take Divisadero Street to Highway 101N (Lombard Street) and exit for the Exploratorium where you can see the swans swimming in front of the Palace of Fine Arts.  Then get back on Highway 101N to cross the Golden Gate Bridge.  On the other side of the bridge, skip the lookout on the east side of the bridge where most of the tourists park and turn left on Alexander Avenue to Conzelman Road, where there are many scenic overlook stops.  From this side of the bridge, you can get part of the city in the background, if you're lucky.  I was unlucky because of a massive sheet of fog decided to roll in and just sit on the bridge.  I only got a quick, 5 second glimpse of the top of the bridge.  Of course all other times when I wasn't near the bridge wanting to capture the perfect photo it was perfectly clear of fog.  Ugh!

So that's it: SFO in a day!  Hope you didn't also want to eat or sit down because there's no time for that nonsense!

Other trip details...

 Hotel:

We stayed at Hotel Diva in Union Square.  The name made me laugh, and the sexy B&W photos of stockinged legs and corseted torsos on the window shades of the room were quite a silly surprise.  We were in a Junior Suite that had a second murphy bed, and the bathroom was super tiny.

Nightlife:

FYI kitchens in the city close by 10pm and bars close by 2pm, so make your plans for dinner accordingly
  • Martunis (4 Valencia Street) - an amazing "local bar" find in the Midmarket neighborhood just before you hit Castro.  In the back room, there's a piano bar where you can sing with the pianoman.  I responded to my friend's challenge and got up to sing a 1960s folk favorite that also referenced the San Francisco/Haight Asbury time - "Leaving on a Jet Plane" by Peter, Paul, & Mary.  The crowd is the biggest mixed bag - from casual (even saw two girls in hospital scrubs) to dressy, gay and straight, young and old...everyone, just hanging out, drinking martinis, and having a great time singing along to familiar tunes.  
  • Rasselas Jazz Club (1534 Fillmore Street) - in the jazz district, this bar had a great live band playing recognizable funk songs.  
  • Balboa Cafe (3199 Fillmore Street) - among all the Marina neighborhood young, straight, and see-and be-seen crowd, this bar was a little less crazy and less like a fraternity with the spilled drink slippery floors and stale beer smells.
Restaurants:

Definitely none that I would recommend!