College is kind of weird, but it's also fraught with hierarchical issues. There are lots of things that only freshmen do, and if you know what's best for you, you should probably shy away from doing these things.
1. You're wearing a lanyard with your BuckID around your neck.
This is one of the biggest and most common ones. I know it's an easy way to bring your BuckID around since you need it for just about everything, and I'm honestly not really sure why this is limited to a "freshman thing," but it's one of the biggest identifiers of someone who's brand new to campus. Just buy a phone pocket or carry around your wallet like an adult. I know it's just another thing to remember, but honestly, you'll regret it when you're instantly identified as a freshman.
2. You travel in packs.
For some reason, freshmen travel in packs to literally everything. It's a nice way to get to know people I guess, but if you're traveling with 20 people to a frat party, people will know you're too scared to go alone or with a few people because you aren't used to the environment. If you really are afraid--and understandably so--to approach that frat house, pick a few friends and split up so you can enter at different times.
3. You're obsessed with school traditions.
It's okay to be proud of your university--we all are! But when someone yells O-H and you enthusiastically respond with I-O, they'll probably go, "haha, freshman." It's really only acceptable at sporting events and when you're showing your family around campus.
4. You only go to Scott and the Union.
You probably ate in the Union for orientation so you're familiar with it, and people often talk about Scott because it has such a wide array of foods. But there are so many dining locations on campus that are even better than these two places. If there's a line outside of Scott at noon, it's safe to say the freshman haven't figured out what Connecting Grounds or 12th Ave Bread Company are yet.
5. You go all-out with your "going-out" clothes.
Crop tops and high-waisted jeans are perfectly acceptable and low-key clothes for going to parties (or the bars if you're ballsy enough). You don't have to wear a leotard, short skirt, hoop earrings, and dramatic eye makeup to get attention. The older you get, the less effort you put into your appearance on the weekends.
6. You exclaim, "they sell whole pizzas here?" the first time you go to Marketplace on Neil.
Yes, yes they do. That is why you are able to order them. They're not that big, and it's a great size for one person, so don't get your hopes up. Wait until you find out about the PAD.
7. You're constantly looking down at Google Maps.
It's the biggest campus in the Midwest, but honestly, you should be able to figure out where your classes are within the first two or three times you attend them. There is very little reason for you to not know where your classes are, even if the campus takes 20 minutes to walk across.
8. You can't figure out how to swipe your BuckID on the COTA.
One of the best things you pay for in your tuition is the ability to ride the COTA for "free." If you get on the bus and can't figure out how to swipe your ID, here's a tip: turn it upside down and backward. You're welcome!
9. You take the elevators in your classroom buildings (unless you have accessibility issues, then disregard).
Unless your classroom happens to be on the fifth floor--it probably won't be, honestly, since most of the classroom buildings are, like, two floors--you don't need to be waiting for the elevator. You'll learn pretty quickly it's much faster to just jog up the stairs to the second or third floor.
10. You don't know the words to Carmen Ohio.
Oh, for the love of all that is scarlet and gray, learn the words! You don't have to know them as soon as you step foot on campus, but it'll become very important when you're standing with your fellow Buckeyes in the student section in The Shoe before and/or after a game and you're faking the words.
It's an amazing thing to be a Buckeye, but if you're not careful, it'll become glaringly obvious that you have no idea what you are doing.