The eyes are the big deal. If you ask anyone about the style of anime/manga they always comment on the eyes. I put this tutorial together as a primer. There are literally thousands of styles of "Manga Eyes" so there is no set rules for drawing them..just a few consistant traits. Below is an approach to a broadly used generic style. Adapt it to suit your own needs.
(eye side view tutorial to follow)

Step 1: Ball

As with most things..the eye also starts as a circle. This represents the orb of the eye and helps with the general placement of the eye in the skull.

Step 2: Lids

Here's where most budding artist go wrong. The Lids wrap around the contour of the orb. Imagine streching a sheet of rubber over a cue ball. The Eyelid hugs the curvature of the eye.

Step 3: the Pupil

The eye in a relaxed state hides some of the pupil and iris behind the lids. Notice how the iris takes up most of the surface area of the orb. This occurs only in Anime/Manga and a few black velvet posters from the 60's.

Step 4: Long, Lush Lashes

Up until now the eye was kinda "Blah". Flesh out the eyelids with some heavy duty, fluttering lashes. This adds weight to the eye so it's not ust floating around on the face. It also draws the viewers attention. The thickness of the lashes will depend on a character. Obviously Male characters won't have this trait and younger females should also have a thinner line. This eye is more for the sexy adult female

Stroke Order:

I didn't really have this part down until I started studying "Kanji". Japanese Kanji is produced by a series of strokes in a specific order and pattern. I find this order also works well for eyes.
1) start light and press harder as you move to the outside.
2) Start harder and lighten pressure as you move down
3) Start medium and lighten pressure as you move down
4) Start light and increase pressure as you move to the outside.

Step 5: Spectacuar Speculars

A "Specular" is the reflection of light on a reflective surface. In this case, the eye. The placement of the specular on the eye should be indicative of the light source..If the light is coming from the upper left..the specular should be on the upper left of the iris. in this case, The light enters the eye from the upper left and exits through the lower right.
In Manga, Speculars are also used to add emotion to the character. It adds sparkling life to happy eyes and quivering tears to sad eyes..