There are 2 things to keep in mind for maximizing battery life:

1) Battery Charge for Storage

LiPos should never be stored with a full charge. The proper charge level to store a LiPo is under 50%.

2) Proper storage temperature to maximize battery life.

A battery creates power via chemical reaction. Heat speeds up the reaction and cold slows it down.

If you plan to have a longer break from flying, the best way to store a battery is in a fridge, inside a plastic zip top storage bags.

Permanent Capacity Loss versus Storage Condition

Storage Temperature
40% Charge 100% Charge
0 °C (32 °F) 2% loss after 1 year
6% loss after 1 year
25 °C (77 °F)
4% loss after 1 year 20% loss after 1 year
40 °C (104 °F)
15% loss after 1 year 35% loss after 1 year
60 °C (140 °F) 25% loss after 1 year 40% loss after 3 month

Do keep in mind to never leave a pack fully charged or at room temperature for extended periods of time.

Take care of your batteries and they will last longer.