The outmost easiest ear to draw is the one which remains hidden behind some strands of hair. But unfortunately that’s not always the case (a cheer for long hair!).
Therefore I sat down and tried to sketch different kinds of our organ of hearing. As you can see, some of them belong to humans and do only differ in the perspective from which they were drawn whereas the other ones belong to legendary creatures (well, whether Yoda belongs to them or not may be under discussion, but still: Legendary he is). The reason why I chose to add some inhuman ears to the collection is that every time when I’m thinking about ears, elves do cross my mind. Dear me, how I’d love to have such elegantly pointed ears… With them even sticky-out ears could be called “lovely”.
When drawing ears it’s not essentially to outline an exact curve. Some people have pretty uneven external ears and it won’t strike somebody as odd when the shape is a little edgy (see the ear with the earplug). On the other hand it’s important to pay a lot of attention to the “inner ear” (correctly speaking, the part I’m referring to the “inner ear” right now isn’t anatomically the inner, but as well part of the outer!). I’ve seen a lot of amazing sketches where the ear was messed up because there wasn’t any coherent structure. Don’t get me wrong, the actual ear is different from individual to individual and therefore can be shaped differently, but still, you have to know very clearly where the cartilage faces outwards and where it’s curved inwards. So you won’t try to join a line indicating a bend outwards shape with the line belonging to a dent.
I know, explaining isn’t my hobbyhorse (I’ll try to get better, promised). Nevertheless I hope I was able to give you some inspiration for your own ear (if you are busy creating your own legendary creature) or just some reference for drawing the ear of a normal human being.