There are a ton of independent small gallerys in san francisco where you can see new, and up coming artists. They typically change artists each month, sometimes sooner.
STUDIO Gallery-1815 Polk Street
The Shooting Gallery-839 Larkin St
Receiver Gallery-1415 Valencia St
The Space Gallery-1141 Polk St
FIFTY24SF Gallery-252 Fillmore Street
City Art Gallery-828 Valencia Street
111 Minna Gallery-111 Minna St
Southern Exposure Gallery-417 14th St
Gallery 444- 444 Post Street
These are just a few, there are gallerys all over San Francisco!