Some are easy - citrus and spice notes can easily be learned from a trip to a local Supermarket! - but some are trickier than others. If there's a place that sells essential oils near you, it might be worth smelling the various bottles ( many places have testers ). Other notes are learned by experiencing them in perfumes that are dominated by them, such as musk ( very few people have ever smelled the real thing ). However, some notes are marketing speak that you needn't bother learning: "pink frosting accord" etc.