Teach responsible members of your family how to turn off gas, water and electricity at main switch and valves.
Shut off gas only if you suspect a gas leak or can smell escaping gas. The main shut-off valve is located next to your meter on the inlet pipe. Use a wrench and give it a quarter turn in either direction so that it runs crosswise on the pipe. The line is not closed.
After the quake make a visual inspection for leaks in your plumbing system. If leaks are discovered, shut off the water at the house valve. If the house valve does not work, shut off the water at the meter (located in a concrete box in the sidewalk).
Know the location of your main service switch handle - to cut off main power supply-and your branch circuit panel.