When driving in the rain, you should slow down, increase following distance, and avoid hard braking. You should also use your headlights, defroster, and wipers to maintain visibility.
Speed
Slow down and avoid using cruise control
It takes longer to brake on wet roads
Following distance
Leave more space between you and the car ahead
You'll need more room to stop safely
Braking
Avoid hard braking, which can cause your car to skid
Braking times are longer in the rain
Visibility
Turn on your headlights, even during the day
Use your defroster to help clear your windshield
Use your wipers to clear away water
Avoid brights, as raindrops can reflect the light into your eyes
Other tips
Avoid large vehicles, which can spray water on your windshiel
Use your air conditioning to prevent condensation
If you aquaplane, take your foot off the accelerator and don't brake
Keep your car well-maintained, including your headlights, taillights, and windshield wipers