You need to practice having conversations with strangers. You need to learn to sustain a conversation. I'm a natural introvert, but I learned to do it. You can, too. Just practice starting conversations in the line at the grocery store or on the bus or in elevators or with co-workers you don't know well. You will improve with practice.
Look for a book about interviewing skills. Most of the preparation tips will be useful for you.
http://money.usnews.com/money/career...interview-prep
Practice active listening skills.
http://sales.about.com/od/wheretosta...-Listening.htm
Here are some suggestions for recruitment:
http://www.greekchat.com/gcforums/sh...t=conversation
http://sororityrush.webs.com/preparationii.htm
http://www.suresister.com/sororityre...-conversations