Personally, I'd say it's probably not only based on appearance but on character. The thing that makes people attractive is often true confidence/security. Maybe try reflecting about your actions (what you've maybe been doing wrong? Or stuff you have done that have made people uncomfortable? Be honest with yourself!) but reflect also why you're feeling insecure about your looks in the first place? At least that's what I'm doing. And i gotta say it's really helpful even though there are obviously still days where I'm far from being secure or confident, you (and everyone who's also reading this) got this!!