This quick tutorial illustrates how to draw anime and manga ears from the side, front and back views and explains where to place the ears in relation to the head.
Anime and manga ears vary in styles from more realistic to very simplified but there really is not one defining way to draw them.
It is also difficult to have clear guidelines for drawing ears in general because of their irregular shape. One good thing to do is to simply look at some examples as shown in this tutorial or at photos of real ears if you are going for a more realistic style.
When drawing anime ear from the side view it may be helpful to think of it as an oval or an egg that is tilted to one side.
More realistic/serious anime styles tend to draw the ear closer to traditional art while other simplify it to to just a few lines.
Placement of the Ears on the Head
For horizontal placement draw the top of the ears close to the bottom of the forehead and the bottom of the ears close to the tip of the nose.
For vertical placement draw a line down the middle of the head and draw the ear just a little bit to the side of that line.