Ears come in all shapes and sizes. They can be pointed long, or small, rounded or pointed at the top, have thin lines or be more "fleshy" and so on.
The tricky thing about drawing ears is that it is a very complex area that includes a lot of different shapes.
In the sketsches below you can see three different ears from a lateral perspective.
The outer helix and the ear lobe are the easiest parts to draw. In addition to that, the outer part has a lighter shade du to the direct light. The beginning of the ear canal is usually the darkest part.
To draw the inner part of the auricle is almost like drawing a complex hilly landscape. It is important so see the roundings and to find out where the dark and light areas are. Then try to draw the shapes.
Below you can see two ears from a frontal perspecktive. Both ears are covered by a bit of hair.
You can see the ear lobe, the helix and the crest on the inside of the external ear. In the example the left ear the "Antihelix", the crest on the inside, is rather dominant. Therefore it is always important to look closely at each ear.
If you have trouble to see the structure of the ear, take a look at the anatomy of the external ear.
In the Pons "Bildwoerterbuch" is an example of the auricle: http://bildwoerterbuch.pons.eu/en/human-being/sense-organs/hearing/auricle.php