The enemies of olive oil are air and sunlight which cause oxidation and loss of flavor. There are many ways to protect your olive oil, but the most popular is to store your oil in a tinted bottle with a spout.
I also like using an old enamel coffee pot, a trick I learned from Sam Clark, chef and owner of the Moro restaurant in London.Mr. Clark recommends enamel coffee pots because they pour so well. I like them because they also prevent damage from light, and I'm partial to their looks. I keep a small one in my kitchen, not too close to the stove, topping it off from my bulk bottle as needed.
I go through olive oil fast enough that I don't feel the need to plug the spout to prevent further exposure, but if that's a concern to you, just find a suitably sized cork. I also agree with Mr. Clark that a primary reason to use the pots is that they pour in a nice even stream. Many spouts and olive oil bottles glug and gurgle and even require a shake or two.
The enamel coffee pot pictured above is from Kiosk, $60. You can also find less expensive ones online at Etsy and eBay and even better, in thrift stores and flea markets.
Related: Lunch Hour Video: How to Make a Moro Dinner at Home