Basically, after you beat one or two nations, you've seen all there is to see.

Basically, just do tons of investment in education/technology- schools, libraries, tech colleges.

Meanwhile make sure you put pollution controls in early, along with minor stuff like telecommuting and bus lanes.

Once your GDP goes up, you can invest heavily in community policing, prisons, and a well-funded police force- as long as you don't adopt any stricter policies, that's usually enough.

Immigration, as far as I can tell, only has negative effects. Make it as restricted as possible.

Finally, in mid-game, invest in state health care, state housing, and state schools, depending on what you need.

Aaaaand, that's basically it. Sometimes you have to adjust a bit- increase military spending, or institute gated communities to appease the wealthy/conservative groups... but really, this post will get you 80% of the way to a victory.