The best way is probably to service it first and then close it away. Then when you get it back take it for a good run. Id take it for a good run first before turning off so that youve cleaned everything out in the engine and removed as much moisture as possible from the oil.
Its abit drastic but they sell a item called a battery maintainence device. It keeps topping up and applying a small load and then recharging, so that the battery doesnt go dead. Im not sure how much they are.
If you dont get one, id take the battery out of the car, or best case senario get someone to drive it once a week.