Derek Powazek wrote a great blog post with ten very helpful tips on how to be a driver in The City. I read through these and can say that they are all reasonable and actionable. The only tip I would add to the list is that if you are a serious San Francisco driver is that you should know all of the events going on in The City at all times. San Francisco is very small and any event causes a huge traffic backlog.
You should know the one day a month when Critical Mass is taking place (last Friday of every month). You should know when parades (Folsom Street, Haight Street Festival, Gay Pride), races (Bay to Breakers, SF Marathon, AIDS Walk), and street closures (JFK in Golden Gate Park on Sundays, filming downtown) are happening to avoid being stuck in traffic. The days when these events are happening are walking days, period. Only advanced drivers should attempt to drive around major events while they are taking place.
Send your friends a link to Derek’s tips next time they come into The City and check the event schedule while you are at it. If there is a parade or major event that day, just tell them to take BART or MUNI coming in. Good luck drivers!