A few simple items of maintenance should ensure your car runs faultlessly for the winter. It is no use the most useful tool you have breaking down when you need it the most. So winterise your car by getting it checked out by a local garage. They'll assess the condition of your battery, top up the fluids and make sure the anti-freeze is at the correct level. While there, check the condition of your tyres, as the tread depth is crucial for clearing water and providing grip on wet winter roads.
If you're really serious about keeping mobile then you could invest in some snow tyres or a set of snow chains. They're mandatory in many parts of Europe and provide quite phenomenal grip when there's snow on the ground. A bit extreme perhaps, but if you need to keep motoring regardless of the conditions then snow tyres or a set of snow chains in the boot are exactly what you need.