It has been my habit drawing an eyes anywhere and anytime. When I'm bored, I will draw and eye even inside the class and our subject is boring.

Some artists I know started with sketching an eye. Most of them are self taught artists like I am. I drew this earlier because I was bored hahaha.

I'll show you the step by step process I did with this.

first thing I did was the outline of the eyes.

Make sure to just draw it lightly because this is just an outline.The outline doesn't need to be perfectly sketched. It will change later anyway so this will just your guide for the shape of the eye.

I darken the pupil of the eye

I left a space in this part if you can see (the box) where the highlight or shiny part will be placed later on.

slightly smudge it

Using a blending stump, I smudged the the iris. You can also use tissue or your worn finger to smudge it. Make sure to smudge it lightly to make it look kind of smooth.

put some strokes

Using a 4b pencil, I put some strokes around the iris leaving the highlight (the box) still empty.

did some smudging here

adding some details

Using 2b and blending stump, I start adding some shades around the eye to add depth in the drawing. This will make the drawing like semi realistic. I don't aim it to be so realistic so I didn't focus on other details that much.