First, you'll have to distinguish between the pupils and the flesh covering the eyes. There's a big difference. Many people don't, or even never, notice the pupils. Look at the picture below. Find the black circle in the center of the eye. It's right in the middle of the yellow orange color. That black circle is the pupil. Meanwhile, the yellow orange one is the iris.
http://upload.wikimedia.org/wikipedia/c ... 7s_eye.JPG "A woman's eye." by Petar Milosevic | Creative Commons Attribution-Share Alike 3.0 Unported license from Wikipedia.
When a woman likes you or is sexually attracted to you, that pupil will grow big occupying almost the entire iris or yellow orange area. Some people have (instead of yellow orange) brown or grey irises surrounding their pupils.
When a person is sleepy or is exposed to very bright light, the flesh covering the eyes will hide the eyeballs to such an extent that the eyes look small. This does not necessarily mean that the pupils are small. On the other hand, when a person is wide awake from taking too much coffee, the flesh covering the eyes will expose a bigger portion of the eyeballs. Again, this does not necessarily mean that the pupils are likewise bigger. The pupils could be smaller in relation to the iris even when the flesh covering the eye is wide open.
Second, you'll have to practice looking at the pupils. Here's a training exercise to do this:
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Third, women are very subtle creatures. Unless you have built wide and deep rapport with them, you cannot just tell them straight to their face that they are attracted to you without them denying that they were checking you out.
Fourth, a woman can fake a repulsed look by raising an eyebrow, frowning her forehead and then pouting her mouth but she can never fake her sexual attraction to you through dilated (bigger) pupils.
In this case, talk to her while looking directly at her pupils while you're imagining that your cock is entering her pussy. Just look at her pupils. Don't look at her boobies or anything. Just the pupils.
Next, invade her personal space without touching her. Her personal space (if you're a Westerner, Asians have a closer personal space) should be around 2 feet to 18 inches. If she doesn't pull back, hold her hand and continue talking. Check out Warped Mindless' Complete Day Game Guide at the PUA Lounge for the next steps, here:
complete-daygame-guide-vt133745.html.

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Approach. Open. Escalate. Isolate
Here are my two essential rules on texting that will save you tons of time and money:
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