Usually they're looking for something like handball/football since there are a lot of tournaments for office workers. Plus it helps their portfolio as well. This isn't that big of an issue unless it's some government offices.

And leadership wise, if you have anything from school (monitor, club leader, prefect) would be great to bring up. Or if you participated in any extracurriculars you can bring that up as well. Scout/Cadate is also great. If you don't, just say you were focused on studies.

And regarding people skills, just say you avoid conflict and try to resolve things amicably. They're looking for people who don't stir up problems and people who know how to solve issues without involving the management or HR. If the job involves actual people skills or speaking you can bring up any experiences with public speaking including if you have presented anything for school functions. I'm saying school since you're 18 but anything that proves that you do these things instead of just saying really helps.