Check the alignment of the two pupils by laying your pencil horizontally across them, making sure you are holding it straight and not tilted. Looking at your artwork in a mirror is a foolproof way to spot errors. In this instance, you could clearly see if one eye is larger, or lower, or out of kilter in any way. Correct any errors you find. Add whatever accents you see in the eyes that will bring your drawing to life.
Eyes are great fun to draw.
As you draw other peoples eyes, try to get the age group right. For example, glamorous eyes with long sweeping eyelashes would be inappropiate on a child. Some eyes really do sparkle and dance. It's safe to say you will never be bored drawing eyes, for everyone's eyes are unique. The variety is infinite.