For starters, when I normally draw any pictures of eyes, I do the drawing from memory or from my reflection in a mirror. I chose to take a picture instead as reference, this time. This is Sarah's eye.
I took the picture to my computer and blew it up so I could see it easily.
Then I began sketching out the basic lines of the eyes. I usually begin with the teardrop. I'm weird that way.
Congratulations me! Already it looks like an eye.
The top of the eyelid, or as I've heard it called, eyeflap. Often the eyelid line has a vaguely squarish shape.
By the way, the eyelid does not lay flat against the eyeball. It's, I don't know, a half a centimeter thick, so it has an edge that's visible on the lower side at the angle. (That sounds super intelligent of me). Also, with all the eyes I've closely examined (meaning, no one's eyes outside my family), there's a subtle wrinkle on the lower lid, as you can see.
I put a little line where the eyebrow will be, and began to mark out the shape of the iris.
You may have to erase and redraw. As you can see.
I began shading the eyeball, and added the pupil. I had to redraw that part too. Depending on what the lighting's like, it'll be bigger or smaller... so long as it's round.
Shading the iris. Using light lines, and keeping in mind that the outer rim of the eye is usually darker than most of the iris. Once in a tutorial I read that you should be very careful to keep all the lines pointed toward the center of the pupil, so, respect the master, whoever they are.
Fleshing out the eyebrow more, and adding more shading...
The beginning of eyelashes! Keep in mind that eyelashes are curved, not stick-straight, so they go down slightly before they go up. Also, as I've heard and observed, the eyelashes are rarely seen individually, but stick together in clumps. Pretty clumps.
Adding lower lashes. Smaller than upper lashes, and a lot more scarce.
Darkening the pupil. Pupils are like, really black. I added a bit of shading around the eye (you may not be able to see it). For the most part, I'm done now.
So I hope this was at least vaguely informative. I'm not any sort of expert, I'm a sixteen-year-old girl, not Van Gogh or Michelangelo. I just like doing eyes. I have eyes. You may also have eyes. Eyes are good.
Update: Here's the image superimposed over Sarah's eye. You can see here that the eyebrow I've drawn is not proportioned correctly and instead should be much larger in comparison to the eye (and it's not just Sarah, she's got much thinner eyebrows than I have). That's one last tip, then. Well, maybe fuller eyelashes.
To God be the Glory,
Hannah