Don't wait until you actually see lightning in the sky; give yourself plenty of time to seek shelter.
Immediately go into a large building, if possible.
Don't use the phone except in emergencies. If a telephone pole is struck by lightning the current can run into the phone wiring of a house -- and right up to the receiver.
Don't be the tallest object around. Lightning strikes the highest object, which could be you if you're in an open field or on a hilltop.
Stay away from other tall objects, too, such as isolated trees, umbrellas or the mast of a sailboat.
If caught in a forest during a storm, seek shelter in a low area under a thick growth of small trees.
Move away from open metal vehicles such as construction or farm equipment, bicycles, golf carts, clubs or other metal objects.
One of the safest places to be is in a car (not a convertible) with the windows up. Do not touch anything metal inside the vehicle.
Out on a golf course, try to find shelter under a building or a clump of low trees.
In a boat, lie down or get below deck, if possible.
On a field, get to your knees (don't lie down; you want to minimize direct contact with the ground) and keep your head down until the storm passes.