I learned a lot about how agencies work, and how different departments interact. I also learned about client interactions and developed skills that will help me find a job in the future.
What I wish was different
I wish there had been a more structured plan in terms of my one-on-one interactions with my supervisor. She was very busy and was out a lot of the time. It's not her fault, that's just the job, but having more interactions would've been helpful.
Advice
Get your foot in the door. Especially as an intern, just get in the building. You'll have the opportunity to learn whatever you want once you're there.