This is how I draw eyes.
sorry its so rough
To keep them consistent it's important to see the face as if it were 3d.
the cross lines help to do that, and then simply drop them onto the face where they should be.
the most important thing though is looking at it in 3d, if u dont do that then things will look flat, or the second eye " is bigger than the other, they look weird..."
anyways, hope that helps a little?
also
please check out this topic i just made if u need help or want to help others on their art.
Art help. Post your art