If refrigerated olive oil will become cloudy. Just remove from the refrigerator and let it stand until it returns to room temperature, at which time the cloudiness will dissipate and it will be clear again.
Olive oil need not be refrigerated because of its high monounsaturated fat content. Just make sure it is stored in a dark, cool dry place. The cabinet is fine so long as it is not near the oven or any heat source.
All the above advice are true - Olive oild needs darkness to be closed shut and chilness.
You do have to remember that even a good olive oil has a maximus year of shelf life before detoriating and turning rancid. An olive oil with less acidity (an extra virgin by definition has less than 1% but some good brands go as far 0.35% or even less) last longer. Filterd last longer(but alas has less taste).
Check vintage dating when you can. You should remember that if you buy around the harvest season most chances it's already at least a year old. At least a year sitting in not the best conditions on a store's shelf or hot back room.
The harvest seasons starts around september and ends up for some variaties around december. So unless you but straight from the presser(Like lucky me has been doing most of his life, at least before i move to the states) try buying it around now march april. Buy now for the whole year(after making sure it is from the last harvest, and then keep at the conditions refered to in previous posts.