You might be surprised by some of reasons you get a ticket
Curbing wheels improperly
This is probably a no-brainer for most San Franciscans, but I see it a lot, and I think it needs to be said. Many drivers take the meaning of curbing wheels to be that their wheels must touch the curb. This is not the complete definition. The purpose of curbing tires is to prevent runaway cars. The rule of thumb is that you can be ticketed on any perceptible grade. In actuality it's a 3% grade, but that's really not very much. When in doubt, curb it.
In order to actually curb the wheel, your tires must be pointed towards the curb, not just touching the curb. Keep turning that steering wheel until you can turn no more. Let your car's tire rest on the curb, then you should be good to go.
But, it's a holiday!
Not all holidays mean free parking, but there are some. Take a look at the SFMTA's official list of scheduled holidays.
In my own driveway, really?
This one can be really frustrating, but it's for a good reason. A car blocking the sidewalk can create hazards for people with disabilities. Even if your car is in your driveway, if it's sticking out, you're up for a citation. SFMTA mentions it here