I think it comes down to knowing your own strengths, skills, resources and interests and thinking outside the box for how to apply them - and just reaching out to other people. That step can produce some really neat results.
One of the things that has really bothered me was watching everything that was happening in Syria and all the mis-information in the west or just plain ignorance. Peoples thoughtless comments really bother me, I felt like people just didn't get it. Syria is one of my favorite places, I feel a deep connection to the land and the people. I wanted to show people why it mattered to me, so I decided to put on a show of my travel photography in our local art gallery on the 4th anniversary of the conflict.
I wanted it to really hit home so I did a bunch of research and compared death numbers to towns and cities in BC and in Canada. In the process of my research I came across a newly formed Canadian group who had doctors traveling to Syria and organizing medical training and humanitarian aid called the Canadian Medical Relief Organization. I wrote a fax to the Doctor in charge, and to my surprise, he called me the next day. He and a colleague had just gotten back from Syria and had some very harrowing tales to share. They ended up sending me some pictures of their work, the bombed out hospitals and villages, the children and people, the affect of war on the landscape, and said I could use them in my show. Many of the pictures where haunting, beautiful, devastating.
I organized the show so it started with my travel photography, the "before" pictures, used a shot of Krak des Chevaliers getting bombed as the transition picture (placed right after my photos of the place) which moved into the pictures the doctor had provided, and information about the work they were doing and how people could get involved. For opening night I made a bunch of Syrian dishes and invited our community out. The show was up for 15 days and we raised over $1,000 in donations. For our small community it was a sizable amount considering most people who came to the show didn't know where Syria was before they saw the show.
I think the first step is education, because we can't change what we don't understand. Then I really think that reaching out to other people and finding complimentary people, organizations and ideas so we can make a bigger impact then each of us alone. Also - not falling into the thinking that as one person you can't do anything in the face of such massive hardship - because you can be the catalyst for something bigger then yourself.