I saw a short interview on Twitter a few days ago. A woman, who had just saved a man's life during the terrorist attack in Christchurch, described why she had done what she did. The reporter tried to describe her as a hero, but she shrugged it off. "Im no hero, you just do what you do at the time".
But that is really what makes a person a hero. Simply doing what needs to be done at the time, with no immediate regard for your personal convenience or safety. Very few people set out to be heroes, and of those who do far too many end up being more or less villainous instead.
No, the best way to be a hero is to simply be kind, always, and to make sure to help people that get in one's way when they need it.