Be aware that the life of olive oil is cut short by light and accelerated by heat. Light causes photo-oxidation of the oil leading to rancidity, so dark glass bottles are preferable to clear glass.
Once you get the oil home, keep it in a dark, cool place. The refrigerator is too cold – most olive oils become thick and cloudy, and may not recover their aromas and flavor at room temperature. Once a bottle has been opened, it is best used within 8 weeks; don’t wait for special occasions.