Best thing, aside from finding a covered lot, is to apply a good sealant and wash car regularly to remove salt. Maybe even a car cover, I am not to sure on that but there was an earlier thead on car covers.
My neighbours garage is full, i cant park my car there but he moves his cars outside in the day time to use his garage for his welding work... anyways he will let me clean my car in there, so that its not too cold... but i cant park there =(