This is going to be quite a negative post, at least in the beginning. I just think I should warn you of this before you begin reading.
Okay, now that you've decided to go on reading anyway, let me start by stating the obvious: The world is not a just place. History tells us about how many people have been killed, tortured and excommunicated, sometimes with the illusion of justice having been done. At best, this justice is administered capricously and arbitrarily. One must remember through all of this though, that these are not statistics as much as they are human lives. Every time a person is sent to jail, exiled, beaten, killed or forced to suffer pain, it is unnecessary. These brutalities are quite simply being imposed on such people, for no reason other than those imposing them considering them just or even necessary.
Dehumanisation of people leads to said people's potential becoming less fully realised. Putting the people through hell on a personal scale is horrific enough - they have only their own lives to experience, after all. But when you consider the macrocosmic effects of such behaviour, it should become clear that if you dehumanise one person, you dehumanise everyone. The pain they feel is going to manifest itself as pain in the greater cosmic environment.
It has never been more clear: Strive to do no harm. To anyone. Ever. Making a single person suffer makes us all suffer. For we are all connected. We are all just slightly different manifestations of a collective consciousness. Why should we harm something we can help grow? We can build on happiness and efficiency to the point that they become self-sustaining. If there is a purpose for the human race, it is for everyone to live in harmony. For 100% of people, and indeed all sentient beings to enjoy their existence, however brief, to the full.
So you ask, how can I make a difference? The answer is simple: Be kind to everyone. Be generous with your time, your patience, your knowledge and your possessions. Develop yourself physically, mentally, emotionally and spiritually, all the time. Seek an education. Strive to be fair, non-violent and efficient wherever possible. Listen to people. Laugh, shout, cry, celebrate, mourn with others. Most importantly, enjoy your life. It gives you greater ability to help others enjoy theirs.