Concealed carry is stripped away, state by state. Forced registration of guns next. Ban on all guns next, with grace periods for turn, probably sweetened with a small buyback. Then local LEO's sent to confiscate guns, legal house searches, possibly dynamic entry in the wee hours. Heavy prosecution of those who use guns held back for protection. Bans on cartridges and reloading equipment.
All the while emotionally captivating stories as movies and television episodes, novels and news/print media.
Once the legal bans and confiscation are finished, about two years, governmental programs will escalate, SS will be heavily regulated, confiscatory taxation or more than one kind. those who have the will to resist with weapons they retained will be dealt with.
Legalization of drugs, with calming type drugs being easy to get commercially.
Final merge into a governed region within a world government, steps taken thereto while above is happening.
It's the way I would do it, were I a tyrannical asshole assured in my heart of my rightness to rule and my benevolence toward the great mass who do not think and cannot take care of themselves.