How to be better?

I f(18) am actually a horrible person and it takes alot to be self aware about it,but now that am older I realise its not okay to judge people or bully someone weaker than you and its not funny it's projecting insecurities even though I know am not a good person I still keep doing the same mistakes almost like a reflex and can't control my mouth sometimes so I just wanted advice on how to self improve and how to move on and be better for myself and the people around me.