Every nation goes through a very corrupt phase during the early stages of their development. This phase occurs while the nation formulates their laws and social conventions. But as these laws are formed and obeyed - and, more importantly, as the country gets richer - corruption decreases.
1. Reforming The Judiciary: The judiciary needs serious reform. First of all, we need to fish out qualified people with exceptional records to lead the reforms. Laws don't make sense if they're not implemented. We must engage these patriots, they are there in our systems. Judicial reforms will be aimed at accelerating speed of judgement delivery, eliminating bottlenecks and bureaucracy in the system that create unnecessary delays and loopholes for exploitation, and reducing fraud to the barest minimum. Edit: Part of these reforms will ensure civil matters do not bug the judicial system by getting as far as the supreme courts. Establish small courts for small offenses, if you've watched the popular "Judge Judy" you'll understand my point. This is a topic on its own but I believe experts can do justice to it.
2. Empower the EFCC: The EFCC should not be another government arm where Nigerians go to submit CVs and get recruited. These guys should posses exceptional psychological investigative instinct and educational records and must be trained periodically. Train them on how to dig up evidence and prosecute offenders, and promote them based on how many cases they are able to dig up and prosecute successfully, not based on number of years put into idle service. Expand the EFCC into every state. Get the system interconnected with technology to ensure that all cases are properly computerized and documented
3. Reform The Police: Police officers should stop being promoted based on number of years in service but on merit. Based on number of high profile offenders and arrests you carry out and solve, you are promoted. If you like, stay idle while your mates are working, till you get disengaged for lack of performance. Ensure that every police station is connected to a central 911 system and all telephone lines in every unit must be active 24hrs with consequences of non-compliance, so that all calls made from the public are recorded and later cross checked by a central system to see if they were followed up by the police unit in charge. Strip the police of every power of brutality or torture and ensure they are trained on ways of digging up evidence and prosecuting crime. Ensure that every police unit records the thumbprint and image and record of every individual arrested for an offense connected to a central database and demand that every unit give a concrete explanation for an individual detained for more than 24hrs at the station - with consequences. Alert the public to call or write to a central system if any of their wards are detained for more than 24hrs and they are denied access to bail the person for any reason. In fact, even if individuals don't call, anyone who has been detained for more than 24hrs will definitely pop up on the system and The head office may demand to speak to the suspect. Install communication and recording gadgets and equipment at all police stations.
4. Whistle blower act: this should in fact be at the top list of government priorities in fighting corruption. Enact that act and protect whistleblowers who can come up with evidence about any fraud cases at work, in the public, or even in suspected cases of bribery or fraud against their bosses, public officers etc. this includes whistleblowing against suspected cases of activities like job recruitments, contract awards, tax evasion, bribery or extortion by any police, EFCC or government official. Put suspects on watchlists and keep on investigating them till you dig up substantial evidence.
5. Technology: in this modern age, you cannot fight crime without technology. Ensure that all government projects and activities are no longer paper based. Build databases for all government agencies and employ database administrators, software developers and IT Professionals across the country to manage these systems. Train and retrain these professionals periodically abroad to meet international standards and practices.
6. Internal Audits: Employ internal auditors in all government institutions who are promoted based on successful whistleblowing of fraud and fraud cases, keep them on renewable contracts instead of permanent employment, so that if they do not perform, you terminate their contracts. Agencies like NPA, NNPC, FIRS, Customs and in fact all government agencies will need many of these, not just 1, because government needs to recover at least 95% of our IGR which is lost to loopholes within these organizations. Transfer these auditors periodically. Someone will definitely blow the whistle for a probe or external audit.