Do you have children? Will you want to drive or take public transportation? Do you like the cool coast or warmer parts of the Peninsula? Do you like the faster, energetic city of SF or mellow suburbs?
The other way to help narrow your search is to determine the price $ and size sqft of home you're looking to get. Do you need a backyard? Room for pets? Garage? etc. Have you checked your credit scores and lined up some financing options?
Once you have answered all or most of these questions you will be able to start selecting areas to look at.
Please feel free to message me and request more information about different cities. I have personally lived next door to UCSF and can tell you its a beautiful area with lots of food, recreation and close proximity to transportation within minutes from all of San Francisco.