With roads covered in water, snow or ice, your car's stopping distances will increase. Too many people leave insufficient stopping distances, even during good weather, so you should take extra care in the winter.
Your stopping distance can double on a wet road, so also consider slowing down generally. Be especially careful in fog because it will be harder to see cars' brakelights, but only use your foglights when needed, because they can dazzle other drivers and make it harder for them to see your brake lights.
Snow and ice make roads treacherous. First thing in the morning or late in the day are the worst times, but always be on your guard for tricky conditions.
If your vehicle starts to skid, don't slam hard on the brakes. Ease off the accelerator and steer slightly into the direction of the skid until you regain control. In winter, always drive smoothly with no sudden inputs.
If you're intending to travel in extremely snowy conditions, fit snow chains.