How To Draw an Eye

1. Before drawing eyes, I observe photos of eyes so I know how to properly shade it. This is particularly good if (for example) you're trying to draw an Asian eye and you've never been very familiar with them.
2. If you want, find reference (this is advisable if you are trying to draw a celebrity. You will need a photo of their eyes).
3. Lightly sketch out the outline of an eye. I did mine with a HB pencil, but you can use lighter than that.
4. Shade in the pupil with a 6b or darker pencil. I shaded mine with a 5b because I lost my 6b. 
5. Lightly shade in the iris. 
6. The iris isn't all just one colour. Add some
   darker parts and lighter parts. 
7. I sometimes add a shadow around the iris. Now, because the eyeball is curved it isn't going to be completely white so you need to add some shadows lightly. Shade in the eyelid. 
8. Eyelashes are easy to draw. Don't draw them straight, they'll look fake. You need to draw them slightly curved and wispy. And they don't all go in the same direction!
9. Draw the bottom eyelashes. Don't make them thick and long because it'll look slightly weird. 
10. Finally, shade around the eye and you're finished!

This isn't for a realistic eye. This is how I draw eyes.