Confirm that your windshields and windows are clean, both inside and out, before driving. Clear your interior windows regularly of smoke residue if you're a smoker.
Check headlights, taillights, brake lights and turn signals. Make sure the windshield wiper motor is functioning and that both wiper blades are not worn down or split.
Turn on your headlights along with your wipers whenever it starts raining.
Drive slower than the speed limit in bad conditions.
Keep a greater-than-normal distance from the car ahead of you to compensate for poor braking conditions.
Pull over when it's raining so hard you can't see the edge of the road or other vehicles. Rest areas, roadside malls and restaurants are the best places to stop until the deluge desists.