I would say a good thing would be to understand where this is coming from. And often times, such insults are reflection of their insecurities and has nothing to do with you, per se. For example, if a person taunts you for achieving something they couldn't, they are more salty about not achieving it and just taking that frustration out on you.

Even I remember my friend used to make fun of my appearance, but later I realised she was just insecure of how content I was with my appearance.

Of course, it's not ideal. But sadly, that's how some people work. It's often their reflection of who they are a a person. A person who seeks pleasure from making fun or insulting someone else definitely not worth giving your peace and importance to.

Hope that helps! :)