Ok, the title is a bit of an overstatement. But corruption is not such a big deal as people here think.
You need three things to combat corruption.
1) Perfectly placed Capital and Forbidden City. Aim for an empire shaped like an "8" with those in the middle of one "o" each.
2) Courthouses. You need courthouses everywhere. Nice little courthouses help alot. You might think that they don't help alot, as a courthouse on it's own is often not enough to even dent corruption. But think of it like food/shield production under despotism. Things might be brighter once something else is added. And that something else is:
3) Keep your cities in We Love the King mode. Now, this can be accomplished using 0% entertainment in a size 12 city on deity without wonders. You get 11 unhappy and 1 content citizen. Now you build a temple. 2 content. A colosseum 4 content. A cathedral 6 content. We now have 6 content and 6 unhappy. We need 6 more content and 6 happy. We can get this with a marketplace and 6 luxuries. (First 2 create 1 happy face each. Next 2 create 2 happy faces each. Last 2 create 3 happy faces each.) So you need to expand/trade aggresively to get luxuries. If you get the full set of 8 you get 20 happy faces from luxuries alone. (Which in our above town would mean that all 12 citizens are happy, and have 2 happy faces to spare.)
LUXURIES combat CORRUPTION. Luxuries are what breaks the game in your favor.
