1. Stay out of the water. This is 100% effective.
2. If you're bleeding, stay out of the water. Again, 100% effective.
3. Don't hang out with seals. Sure, they're adorable. They swim under you and play in the waves and look at you with those big liquidy eyes. They're like dogs except you'll never have to throw them a slobber-dripping tennis ball or clean up after them with a baggie. Remember, though: sharks EAT seals. You don't want to be mistaken for lunch. If there are a few seals hanging around, no big deal, but if there are dozens of them, maybe you should find another place to surf for now.
4. Avoid river mouths and areas where there are sudden dropoffs in the sea floor. Of course, this eliminates a lot of good breaks. If you're not willing to cross so many good spots off your list, then just be aware that you might not be the only one hanging around.
5. Don't surf alone. This won't protect you from attacks per se, but if you do get hit, it would be nice to have a buddy to help you get to shore.
6. Paint a contrasting black and white pattern on the bottom of your board -in one study, sharks hesitated to attack something with this pattern- or snag a decal from www.SharkCamo.com. Will you look like a dork? Yes. But if you're shark paranoid like me, it's worth it. Anything to get the Jaws theme song out of my head.
7. If you hear the Jaws theme song, paddle for shore and hope at least one person paddles slower than you.
8. Listen to your gut. If something doesn't feel right, or if the primitive part of your brain starts shrieking "Red alert!", heed the warning.
9. Relax. Okay, this won't help you avoid an attack either, but seriously. You are something like 2,000 times more likely to get injured in an incident involving air freshener than you are to get injured in a shark attack. Air freshener. (Check the International Shark Attack File and the U.S. Consumer Product Safety Commission injury reports data, I'm so not making this up.) Just keep telling yourself that.
10. Take up knitting instead.