Sharpie Sketches - Horses by ColossalBeltloop . I once heard an artist say that she liked to draw in pen because there was no erasing, and it helped her learn to accept imperfections. That seems like a good (albeit somewhat painful ) idea!
Draw the eyes almond-shaped, and made of several sections. Eyes are recessed into the head and have eyelids, eyelashes, the black pupil and the colored iris. Practice drawing the eye and each part of it.