>>/24370/
With enough practice it's not that hard. You're always kind of smelling the same things over and over and you learn to differentiate between stuff. 

So for bready/yeasty flavors, is it sweet like pastry or brioche or more yeasted like baguette? For fruit, okay, we're getting apple but is green, yellow, or red? Is it underripe, ripe, or bruised (oxidative)? Almond/marzipan is a common flavor in oxidative wines, marzipan being a bit sweeter. 

Also, while a lot of people are wowed by shit like "smells like decaying violets, potting soil, sous bois, dead forest, decaying leaves" (see the insufferable tasting notes of D'Lynn Proctor on youtube), it's not very useful. I try to stick with three descriptors for nose and palate, and really trying to give an impression of "what does this wine actually feel like to smell and drink" because when I'm deciding years from now whether to buy another bottle, just rattling off typical scents is useless.