The above covered most of it- Generally, you can either jack up the car and leave it on stands, or overinflate the tires (40PSI or so) during the winter.
Stabil in the tank is a biggie- add it before you fill up the alst time, so it mixes with the gas.
As for the battery, either trickle charge or remove it- I ahve always just taken mine out, and it has never been an issue.
How is the garage for rodents? Consider capping the exhaust tip somehow (half a soda an works), and stick a couple bars of Irish Spring soap in it to deter mice from nesting. Plus it smells better than mothballs.