Ensure all your windows are clean and free from snow and bring a scraper and de-icer with you. Snow left on the roof will become loose and can drop onto the windscreen during braking, thereby causing sudden and severe restriction to your vision.
Check your lights and indicators as falling snow reduces visibility. Make sure your mobile phone is fully charged. If your car has rear wheel drive the addition of extra weight in the boot, such as a bag of sand or cement, will help your wheels to grip.