First, draw a parallelogram kinda shape. This will be the main base sketch for the eye. Make sure you draw it lightly so you can erase it!
Using the sketch, draw the main 'body' for the eye as seen in the picture.
Draw the pupil for the eye. It should be shaped like an oval. Make sure you don't make the pupil too large!
Draw the eyelashes. (This is one of the easiest parts)
Draw the minor details in the eye. You can also erase the sketch lines now, if you haven't already.
Add three lines above the eye as seen in the picture. This will show that the character had eyelids. (Can you imagine how creepy it'd be to not have eyelids?)
Colour in the eye! You may colour/shade it however you'd prefer.
Add/fix any little details and mistakes and voilà! You have an eye! (Good job, you're awesome!)