Come join Humanity and change the way we do Civilization. :)
Well, kind of a joke in response to a heartfelt question, but not really.
If you're just a human, as opposed to some sort of world leader, the best thing you can do is to be out in the world, pointing out that bad things are bad and we shouldn't do them, and do good things. Don't give leaders and people a pass when they do bad things, or promote bad things, or when they don't speak out against bad things.
The most powerful thing we have is our voice, and propaganda works both ways. In your daily life, be a propagandist for good, both to people around you and to your leaders. Hold people accountable, but have a sense of scale. Be forceful and angry when necessary with leaders, but gentle and helpful with people around you. Don't be a dick. We're all leaders with those around us, but that kind of leadership is best accomplished by example and encouragement, not anger and force.
As for technology:
1. Technology is just a tool, and most tools are good. If you're working in technology, you're already helping civilization.
2. Don't work on specifically bad things. It's good to be a network engineer. It's bad to build or operate systems specifically meant to spy on people and violate the Constitution, for example. [Are you listening, NSA spy?]
3. If you want to be more pro-active with technology, then sure, help build secure systems, don't build or use or promote insecure systems. Show people when they're unnecessarily exposing themselves technologically (there's that voice again). Help people use technology more safely.
4. If your career and interests allow, get involved with the security improvements to standards that are just now getting underway.
Technology is just a tool. It's good to use those tools in defense of liberty, and to make it harder to violate liberty with them. But a more fundamental problem is the people who are using technology and other tools to do bad.
We as people need to control our governments and institutions more actively. We need to be the oversight that we want to see. It's the people that we allow to govern us that's the problem, much more so than the tools they happen to use. We've allowed them to wallow and profit from laziness and greed.
We can choose a better government. We did it here in the US in our revolution, and we've more or less chosen to continue and grow it by peaceful means, not counting the occasional civil war and other unrest. It's being hijacked now, and it would be best to bring it back under control peacefully before it's destroyed by another revolution or dissolved by apathy.
Use your voice.