Skip the high-beam headlights in the fog because fog consists of tiny water droplets that spread and reflect light so it actually making it harder to see when you have on your brights.
Remember always have on headlights, but never brights. Remember to turn on your low-beam headlights to help other drivers see you.
Sharpen your other senses. Roll down your window to help you hear other traffic on the road.
Stay focused. Driving in fog is not a time for multi-tasking. Turn down the radio, stop conversations with other passengers and keep your attention on the road.