The number one cause of death or injury in an earthquake is from tall, top-heavy furniture toppling over. Not only can things like wall units and china cabinets kill, but they can also block escape routes, therefore they need to be fastened to the wall.
The first thing to do is to look around and see if there's a bookcase, entertainment center or file cabinet that can be easily moved to a safer place, and/or if there's a heavy object on a top shelf that can be moved lower down. When you've decided on a location, you then need to secure the item of furniture to the wall, making sure that it's fastened to the stud and not just the drywall.
Flexible nylon straps (as shown), will secure the object in place. The straps will allow it to sway without it falling over during a quake. The straps also help to reduce strain on the stud. One end of the strap is screwed into the stud, while the other attaches to the top of the furniture.
Bookcase straps (see detail) can also prevent injury or damage from falling objects. And while you're at it, you should test the smoke alarm batteries around your home.