Best used for light sauteeing, roasting, salad dressings, dipping, and any cooking that is not going to get super, super hot. Olive oils have a pretty low smoke point (the temperature at which an oil starts to smoke and burn), so they are not good for deep frying, etc. You also want to think about what would taste good with olive oil. French, Italian, Mediterranean, many American dishes, etc…these are good for olive oil. East Asian, Indian…not so much. Obviously it depends on the dish, but you get what I’m saying.
What does extra virgin mean? It’s basically a label that means the oil has less than 1% acidity and was created with a cold-press. Extra virgin is the best type of olive oil, and they come in a wide range of flavors, source areas, and colors. Sometimes you will see unfiltered olive oil, which means that the oil wasn’t filtered after pressing which results in a bit more actual olive flavor. I’ve seen bits of olive in some of these before. The extra virgin oils are really great for dipping, and salad dressings. Taste a bunch of different ones. There really are huge varieties in flavor. Some are grassy, some are citrusy, some have hints of pepper or butter, some are just all around olive-y. People can get as snooty about olive oil as they do wine, so you know, there must be some sort of nuance involved in the taste. Find a couple of nice ones you like!
A little less good than extra virgin (if you call it EVOO, we’re breaking up) is fine virgin olive oil, which has a bit more acidity ad a less refined taste. Good for sauteeing, etc, and maybe the occasional salad dressing. Once you’ve had good olive oil, you can taste the difference (see, there’s that snootiness!)
The following are the last levels of olive oil, and they are pretty much just good for using during cooking where their flavors will not be super noticeable: ordinary, refined, pure, and pomace. I don’t really recommend buying any of these for home use. Extra virgin and fine virgin are where it’s at.
Finally, a word on storage. The main things that degrade olive oil are oxygen and heat. You don’t have to keep olive oil in the fridge – if you do, it will harden and then melt again at room temperature. But please, please, don’t keep your olive oil next to the stove or on a windowsill! The constant heat and light will cause it to go rancid. Same for oxygen – keep a lid on it. If you use one of those fancy pour spout things, get one with a little cap or take it off after use and put the lid back on. The best place to keep olive oil is in the pantry or a cabinet, or anywhere dim and not near a heat source./rant