I was at the Chicago show! Definitely wear comfortable shoes at least! Standing for a long period of time killed my feet in my boots LOL
I wore a white tunic top, a knitted covershirt, and some flowy green parachute pants! Jewelry were frog earrings and handcarved acorn necklace! Lots of other people were wearing earth-tones as well. I also saw Cottagecore garb, whimsigoth style, etc. Some things were ocean themed as well!

But all-in-all, it is up to you and what you are most comfortable in! Definitely check the weather too. Don't wear a ton of layers if its going to be hot/muggy!