It's better to add gas stabilizer to the car fuel tank before you leave.
Without gas stabilizer, gasoline is only fresh for 2 months, which may cause
starting issue when you come back. The stabilizer is available at Walmart,
Target and auto stores.
Someones also suggest to release parking brake to prevent potential issue
that brake pads stick to the rotors. You might want to consider to place
chocks under the tires to prevent movement.