Edit: Oh, I see - you've confused me with the person way up-thread with the $300K income, I'm not the same poster as he. I don't like to reveal my income on the Internet, but I'd describe it as "enough", so, to answer your question:
1.) Be alert to pure, dumb luck when it happens, and willing to take advantage of it - including dropping previous plans - when appropriate. I thought I would always work in small companies or startups, but I applied to Google in the depths of the 2008 recession and somehow was accepted, so I figured I'd give it a try. I've been there 5 years, with a fairly generous option grant, and the stock price has quadrupled in that time.
3.) Be curious about the world around you, and in particular, about what the people around you are doing. Every single job I've had, I've gotten through my network. In some cases, those connections were several years old, but I reached out and asked them what they were up to and it turned out what they were up to needed people.
4.) Don't be afraid to leave when you've outgrown a place.
With one caveat:
>Always hone your skills so that when an opportunity arises, you can pounce.
My strategy has been to follow my passions, which include digging into various technologies that interest me. I don't do it "so that" I can be relevant. I do it because it's fun.
It just happens that, when you get good enough at enough things, you'll find that at least some of those skills are in demand. I know a lot about so many programming topics that one coworker just accused me of having "an encyclopedic understanding of just about every topic."
A lot of people have their curiosity tortured out of them by their experiences in school. Anyone reading HN likely is at least on the road to lifelong learning, so anyone reading this is likely on a path that could result in a strong salary. To those who complain that reading about every latest new technology is boring, I say: Find your childlike curiosity and reclaim it.