How can I make the world a better place?

Make a commitment. Maybe the hardest, but definitively the most fundamental and important step. Most people and organizations don't take this step, so whatever they do, they aren't doing it to make the world a better place. Most of the direction of what is necessary to do to make the world a better place flows naturally from this commitment.

Take ownership of something bigger. If you don't feel like you are a part of something bigger than yourself, it's hard to feel like improving something bigger than yourself. I suggest you aim to make yourself a part of all of humanity and all of the planet. Why stop at something smaller?

Pick a Subject. It can be almost anything. World peace, the environment, recycling, better communication systems, education...

Define 'better'. How often do we hear about making 'computers better'? What do they mean by that? What do people mean when they talk of making the city 'better for our kids'? Define your criteria for 'better' or you'll just be flapping in the wind.

Keep a continual dialog. Chances are you won't be right. Keep talking with those who you respect and your peers and sometimes with those you don't even like. Maybe they have something more radical to teach you or a fresher perspective than those you usually agree with? And then go back, again and again, to keep talking. Talk is never cheap and there is no such thing as 'just talk' if it's part of an active dialog.

Implement something. You don't have to solve the whole problem in one go. Just do something. Just a bit. You'll see, the world will change. For the better.