My first answer is to develop your skills to the point where you are strong on design and UI/UX, not just coding.
I say this because we've worked with some people who have this ability, and they're extremely effective as activists once they focus on a mission.
Aaron Swartz is one person who had this ability, but you don't have to be a genius polymath to be good at this, and Aaron wasn't amazing at visuals and design either. (He was good enough at it though, which was what mattered.)
Ideally, you should be able to speak persuasively online, using text, code and design creatively to get your message across. But as a minimum you should be able to build a prototype from your own vision, get the UI/UX to a point where you're happy with it by iterating, and QA it yourself.
There are a few reasons for this, but the main one is that most social change gets done by small groups of people, and many of those people aren't technical. And usually it leverages certain moments when people happen to be paying attention, and makes the most of those. So you won't have a big team, and being able to do most things yourself lets you respond quicker.
If you have that, I'd try your hand at working on some issues that interest you, either directly, or showing up at an org you admire and seeing if you can help.
We're setting up a space for volunteers, and also a YC-like fund for new activism projects that emphasizes the need for technical founders: http://fightforthefuture.org/ateams/