Decorate it with something related to your school! For example, if you’re going to The University of Arizona decorate it with a wildcat or A symbol.
Maybe you’re not feeling your college school spirit. Stick to your favorite childhood tv show or movie. There’s plenty of options from spongebob to scooby-doo!
Perhaps there’s a lyric/album that you relate to. Try thinking of something that encapsulates your high school experience, like Ariana Grande’s Thank U Next.