The chapters at my school weren't nearly that large, but since no one else has replied yet, I'll try to give you some advice.
You will only have time, during your first round events, to meet a handful of sisters. When the chapter votes on whether to invite you back, these sisters will tell the chapter what they thought of you, and the people who didn't get to meet you will vote accordingly, placing their trust in their sisters. But all your fellow PNM's will be in exactly the same situation.
As you progress through recruitment, you will meet more and more women in each sorority that you return to. This will allow you to get a better idea of which sorority/ies might be the "right" one/s for you. You're still not going to meet all 200+ women in a given chapter during the recruitment process, but that is to be expected.
Try to be memorable, but in a good way. Wear some unusual (but not outlandishly so) item of clothing or jewelry... when the chapters discuss your invitation, they'll be able to say (for instance) "Jenn, the one with the scottie dog pin" which will jog people's memories. You also want to avoid being mixed up with other Jenn's going through recruitment, particularly if one of them is rude, strange, has a bad reputation, etc.
Good luck, and be sure to come back and post about your experience!
