Corruption reduction has a few field proven methodologies. The simplest is to make the penalty for corruption so insanely high that nobody would take the risk. The main problem with that is that you need someone extremely powerful and extremely convicted to make such policy in the first place, and it also usually involves human rights violations. High treason was very rare in England because you'd get hanged, drawn, and quartered if you did, and it was the only crime which resulted in such a crazy violent punishment.
Then there's weaponized pride. Ataturk did this, as did several Central American nations. If you can get people to believe strongly in your country, corruption will take care of itself because people will follow the spirit of your institution. It's a bad idea to offer someone a bribe when they see it as sullying the worth of their great nation. This is effective but difficult.
You can also take the opposite end of the risk-assessment strategy, and make conditions for not being corrupt so good that embracing corruption isn't a worthwhile endeavor. You can do this both with and without simultaneously doing the first strategy. The main problem is that if you don't employ adequate safeguards, the corrupt will just take your benefits and continue to secretly be corrupt.
Finally, there's revolution. Burn it all down and chop the fucker's heads off, you're running the show now. Nothing like a cleansing righteous fire to get rid of corruption. The problem here is that it is very easy to go full circle, or end up even worse than your predecessors.