The first step of activism is to be noticed in a social setting. Let "normal" people see people of your group as "real people." I have seen this over and over. Like a racist person will start accepting a person of a different color once they know them on a personal level. Or a homophobic parent may become more tolerant when their child comes out in the open.
I think polyamory is in this stage, where we are being noticed by society. Hopefully, society will not see our lifestyle as a threat and our rights will grow. It will also grow as an outgrowth of gay and secular rights.
So I see a lot of local activism just by coming out poly. We still have need for more national and international activism, but I think the biggest changes come from the combined local activism.