Stabil or Seafoam in the tank, take it for a drive to get it into the carb.

Disconnect the battery, air up the tires. I use rubber stall mats from Tractor Supply under the entire car, corner to corner, to keep the moisture off the undercarriage.

I like to run a floor level fan in the garage late in the fall and early in the spring when the moisture is condensing daily to help keep it from sitting under the car. I also wash the car a few drives before putting it away, use a very high quality cover, and do an oil change.