You might want to go easy on the jewelry (no large-ish statement necklace or anything) and find some really cute shorts and sandals (a navy shirt should be easy to work with).
Check the websites of your school and schools with similar recruitments for examples -- the PNMs at Mississippi State are wearing Panhellenic-issued t-shirts for all rounds except pref, and there are a lot of examples of shorts with tees on the MSU Panhellenic site (keep scrolling):
http://www.panhellenicmsstate.com/#!about1/cqct