Put a trickle charger on it and change the engine oil. It's better to have clean engine oil than dirty engine oil on a storage car. Inflate the tires. If you can, drive it once a week for at least 20 minutes to warm it up and keep the battery charged. This will also help prevent the tires from flat spotting.
I don't suggest car covers because they hold and rub in any dirt that gets under them or is on the car. Obviously, a garage would be best.