rush

They'll show you a "fashion show" for their suggestions on the first overall recruitment meeting where they give you run-down on what to expect if you're interested in rushing. What I wore for rush last year:
open house - jeans, boots, nice top
sisterhood - sundress, sandals (some people still wore pants/skirts/shorts but all nicer than jeans, a little nicer than open house)
philanthropy - think nice dinner out/brunch with your grandma: nicer short dress with sandals and actually did my hair (doesn't happen like ever) - could still do pants that day probably, just make sure they're super nice
pref - pretty nice maxi dress (do not go full prom, just think like non-black tie wedding), I wore nice flat sandals because I'm super tall, but a lot of girls wore wedges.
Hope this helps! Rush is definitely a lot more formal than most sorority stuff, we wear sweats and tshirts to chapter, and remember that we're trying to make you like us as much as you want us to like you!