From my macro-perspective, the top five avenues of government corruption are (1) red tape in licensing and permits, (2) conflict of interest and rigging of bids in procurement, (3) underpricing in sale of government assets and privatization, (4) conspiracy with evaders of taxes, duties, fines, and penalties, and (5) profit-cutting in infrastructure projects.
Especially in the local level, when public position becomes a family businesses that is passed on from old generation to the new within the same family, the corrupt allies will also just be transferred from one generation to the next. This is one of the reasons why corruption survives through time.