I paint the eyes AFTER I paint the face (and the flesh tones have dried). This allows me to lay in the white paint very precisely, and if I mess up, a little bit of turps will remove the paint so I can start over. Then, when the white of the eyes is dry, I paint the pupils using a dark blue/brown. (Again, if you mess up, swipes the paint away and do it over.) Finally, I lay in a dark brown line to represent the underside of the upper eyelid.
All is possible with the aforementioned W&N Series 7 #000. The bad news...it takes experience and practice to get to a point where you're totally satisfied with the eyes. There really aren't any "tricks" per se.