Always use the highest gear you can to prevent the back wheels spinning. Slow down so that when you go round corners, there is no excess sideways force. Stay well back from the car in front, best to double the normal recommended distances if you suspect ice to be present. Keep you tyres in good condition and at the top of the correct pressure range. Don't pour hot water over the windscreen or door handles in the morning. Plan your journey to avoid any known icy blackspots. Normal practise if the back end get away from you is to steer into the skid but best to keep the front wheels pointing where you want to go.