What would make our society more "just?"?

I need to give a presentation at school about what makes a just society. First I would like to explore some of the biggest problems we face today in society that make it “unjust.” For example some would like to believe that communism is the most just while others a democracy. I think the most just society is one in which everyone can do whatever they want without interfering with other’s free will which I think covers almost every law we have and seems to me like the most fair for everybody.

Anyways I would just like to know what the biggest problems that we face today that make our society (US, Canada) unjust. For example some would say the overwhelming amount of security being forced on citizens for their “safety,” or how there are so many homeless, much poverty, the banning of marijuana… etc. What do you think would make our society more just and fair to everybody?

Thanks! Any help is appreciated!