Often forklift operation requires a spotter. If you are the equipment operator never move if you lose sight of your spotter. Many accidents involve the spotter being injured or killed by the very equipment they are trying to assist.
OSHA has some good tips on being a spotter and using a spotter:
https://www.osha.gov/doc/topics/backover/spotter.html
Train your forklift operators and train your spotters.