I can't believe just how awesome and realistic this is! I love drawings of eyes, and I've seen so many already that it surprises me to spot a good one that impresses me. This one is magnificent. I love the iris, the details on the eyelashes. Perfect
I did a lot of practice - but tip of the day, just draw what you see. Oh, and always treat the whites of the eyes as negative shapes - draw them in first and you should draw the iris/pupil by doing that.