Attend as many events as you can that are hosted by different sororities. Most sororities hold open-house events and mixers before the official recruitment period so unaffiliated women can visit the house and learn about the organization. Don't just focus on one house; the more houses you visit, the more sorority women you will meet and the better you can get to know the system. Check out social events that are hosted by the sorority houses as well; while dances and concerts aren't the best time for in-depth conversations about Greek life, you will gain valuable insight into how the women of that particular sorority will represent themselves and their house when they aren't focused on recruitment.
Talk to girls in different sororities and get to know them outside of class. If you are unsure as to who might be in a sorority, wait for them to wear their Greek letters to class; if you don't know what sorority the letters signify, don't hesitate to ask. Show your curiosity, let them know that you are considering going through recruitment and ask them about their experiences in their sorority. Don't be overly-solicitous or try and force a friendship; treat a sorority girl like any other student with whom you would like to be on friendly terms. If the sorority girl makes a point of inviting you to an open house, or asks you to come to the house to study, take her up on the invitation. It demonstrates good manners and your interest in the sorority.
Be true to yourself and offer the best of who you are at sorority events. Dress and behave appropriately for every event that you attend at a given sorority house. Wear an outfit that showcases your personality and fits the occasion; it doesn't have to be new or expensive, but it should be clean and more thoughtful than sweatpants and a tank top. Remember that you are a guest in the sorority, and while you should be yourself, you should also treat the environment around you with respect. When talking with sorority women at these events, be honest and mention your activities, interests and achievements; sororities often want well-rounded members who will bring pride to their organization. Showing respect for the women and the house and demonstrating what you could bring to the organization shows your interest in the house.