1. rain-x all windows and mirrors
2. carry a roll of "blue" painters tape.
why?
when parking the car outdoors and weather calls for ice/snow/sleet, run a strip of tape along the bottom of the drivers side window/rubber seal. This will allow the window to drop when opening the door.........................and(very important) it will allow you to shut the door when getting in the car.
I have heard horror stories about this. Have not experienced yet(135i has been a garage queen) but, just sold my A4 quattro.
So...........head the warning