Don't use metal objects outside , like fishing rods and golf clubs. Golfers wearing cleated shoes are really good lightning rods. Get out of the water . This includes getting off small boats on the water. Buildings are best for shelter, but if no buildings are available, you can find protection in a cave, ditch, or a canyon.
Tall trees attract lightning.
If you can't find shelter, avoid the tallest object in the area. If only isolated trees are nearby, your best protection is to crouch in the open, keeping twice as far away from isolated trees as the trees are high.