I guess I need to take a look at the list of causes for revolution - I'm getting better, but last game really confused me. I had a pretty big empire (over the pop limit for domination by 1900, due to 2 wars of conquest taking 2 nearby civs) and seemed to be doing great. Looked at my rev page - nearly every civ in my empire was getting worse... I was taking a hit for 'huge empire', and I can certainhly understand that, but the one that was confusing was 'financial trouble'... I had been running the science slider at 70 to 80%, and still making money - so I still don't quite get that one.
I saved the game, went back, and switched civics to a more profiable setup, was making huge amounts of money - still taking a hit for poor finances.
Finally had to go back to the saved game, just cranked up the culture slider and kept enough gold to repeatedly bribe cities as I got warning messages, and managed to hold the empire together long enough for a win, but it was a little frustrating...
I think, as you've said, I need to go get a better understanding of the rev mechanisms. Connection to the capital I learned, and a few others (like civics choices) but the rest sometimes suprise me in bad ways.