One method to deter corruption is the use of an Open Source model – everything’s open for scrutiny. You know how in school you are asked to show your work or justify and defend your work? The same thing should be applied to government officials, who are really working for the people. Any expenses and budget have a corresponding justification and explanation. Also all alternative options that were considered are listed with explanation of why those were not selected. Something like a pros and cons list would help also.
A systematic decision-making tools should be used. Providing a clear illustration of progression in decision-making starting from a wide variety of choices to narrowed down final decision. There are no shortage of tools out there and new one could be developed. The purpose is to make government decisions and budgeting an objective process rather than subjective (which is fraught with individual bias or “trust me” approach).
Possible conflict of interest should also be enumerated. Listing companies or group that would benefit from a decision, or possible connections of a government decision maker. For example, an official who is a former employee of Telecom company had written a law that would result in huge increase in internet rate. This would benefit the Telecom company he used to work for. While that should not automatically be concluded as corruption, it should raise a flag and results in a closer scrutiny to make sure the alternative options are not unfairly set aside.
By having everything out in the open, any corruption could be caught quickly and any trend of questionable decision from an official or government would lead to closer investigation. It will also encourage discussion and even suggestions from other experts and individual citizens.
Another safeguard will be the ability to recall a politician easily. Waiting four years to vote out a corrupt politician is too long. An informal online petition could be used to initiate a recall process against a corrupt politician. If there are lots of signatures (to a set % of voters mark) then a recall process could be started. For example, it could be in the form of a by-election. With ballot question of: to recall or not, if yes choose the 1st and 2nd choice for replacement.