I think you could make use of using sound bites & sound waves in content using your hosts voices and top 5 songs or whatever you’re playing in the station.
Giveaways usually work.
Could also try using “Influencer’s” – maybe get some big name student athletes on the radio or to post on their personal platforms to drive likes/followers.
Ask local restaurants / bars if u can put QR code stickers on their windows/doors/tables.
Def look for opportunities for recurring content (like maybe u do a Monday minute on trending songs and artists and give brief overviews, post song lyrics, anything u can get creative or just make use of hashtags like tbt etc)
Give behind the scenes of the station or the hosts / people who work there.
Be on the lookout for trending things to hop onto as well (for example that duct tape banana thing from awhile go everyone was doing) u gotta be timely tho

Good luck you can try anything really!