I thought the day was nice. The Dean of Admissions is really warm and welcoming. I did start to feel a bit of Zoom fatigue toward the end of the student session, but that’s not anything specific to OSU. The actual interviews were super conversational. Besides a few standard questions they ask, I felt like they just want to get to know you and your experiences.
I think the best thing I did to prepare was know my app really well, check out the SDN interview feedback page, and just practice a few common questions. The best advice is to be yourself. I found the interviews to be really laid back and friendly.