If your hotel is centrally located, the best way to get around San Francisco is to walk. You will be surprised how small the downtown really is. The hills aren't as bad as you think and they get you in shape really fast! Wonderful architecture on every step makes walks so much fun! If you go to a distant location though (like Golden Gate Bridge, or Golden Gate Park, use the public transportation. It's so easy, cheap and efficient. It costs 1$, and you can get a transfer ticket for 2 more hours.
I go nearly everywhere using public transportation. San Francisco has good bus and light rail service for anywhere you want to go. If you're going to be here for more than a few days, consider buying a weekly fast pass for $9.
Muni (short for San Francisco Municipal Railway) runs the public transportation system inside the city, including the cable cars and electric trolleys. They have a helpful website at www.sfmuni.com with maps, schedules, fares and links to a trip planner.
BART (Bay Area Rapid Transit) runs trains from the East Bay through SF to Colma/Daly City. Soon the trains will run to the airport. They have an excellent website with trip planner, schedules etc. at www.bart.gov.
Walk or take the cable car. If you spend several days in SFO, you should get a Muniday-Passport. Three days will cost you $10.00 and seven days $15.00! With this passport you can use every public transportation in town. The cable cars are the most fun, though! If you decide to walk, be prepared to have sore legs and feet after a few hours.
Get a MUNI pass for the city buses. And of course you will need to take a ride on the cable car at least once! The quieter one runs north-south (not so many tourists) but it's more fun to take the west-east route. The car will be full of tourists but it goes up (or down, depending upon your direction) along a very steep hill! Just as long as the breaks will hold.......
Buy a Muni Passport! They are good for unlimited rides on Muni, including cable cars. 3-day and 7-day Passports are good for three or seven consecutive days
Very old trams ticket cost 2USD one way. 6USD one day pass. first lane u can take from Union Sq. Nice trip on streets and mountains.
We purchased the 7-day MUNI passport for $15 which gave us unlimited travel on the cable-cars, buses and metro!