For landings, usually just keep a pair of sunglasses on and take a good seat. The planes are EXTREMELY loud (esp the 747) as they go overhead. On takeoff's, the jets can be very hot, so keep that in mind. Take your hat off, set your beer in between the posts on the road's guardrail so that it does not tip over, make sure your sunglasses are on tight, and take 3 or 4 fingers (whatever you can fit) and put them in the fence so that you don't blow away. When you hear the engines rev up, look toward the water.
If your on the fence, you really don't have a lot of debris aside from the occasional rock. On the beach, watch out for the sand (it can hurt!). On the 747 takeoff, the video starts with the engines just on IDLE! When the camera starts shaking violently and then points at the ground, that's when the pilot advances the throttle. Everyone on the fence had bruises and cuts from debris. I had 2 "scrapes" on my legs, a few bumps on my arms, and I recieved a nice smack on the back of the head from a rock. My sunglasses were also scratched thru the tint.
The best way to keep stuff out of your eyes is to stay off the beach and look toward the ocean.
It's very hot and windy is the best way I can describe it. There was a point during the 747 where I thought about bailing to be honest, it was bad. I can;t imagine what kind of wind speed a 747 at full thrust can generate but I can only relate it to a possible tornado gust? Add the heat from the engines and flying rocks, you get the point.
It's fun tho, everyone should try a takeoff from the fence once while your there.