It always starts with associating those who don't fall into line with a political agenda as in some way evil, once dissident voices are suitability slandered it moves to book burning, all historical truths muddied or destroyed, history its self rewritten. Then create decent and divition amongst the population, turn them against each other, brain wash them into thinking your neighbours and those who are tasked with protecting you are not to be trusted or mean you harm, teardown any symbolism that represents any collective cultural identity to further weaken any collective bond and sense of belonging you have with those around you.
Once you have turned people against each other, destroyed any sense belonging to something greater that one's self, ripped out any sense of identity you can change the social economic structure of a population into pretty much anything you like, isolated, confused and a little bit scared people will look to you to save them willing to make the necessary sacrifices to be protected from whatever danger you tell them they are subject too.