How did the authoritarian and dictatorial regimes that gained power in the years after world war 1 acquire and maintain their power?

They usually got power through violent means such as revolutions or coups or similar things. They would  tell people that there is a common enemy from another country, or from within the country in the case of Germany, and explain that it was their fault for all bad things in the country. When they would get high enough of a support, they would organize violent riots and protests and coups and similar things to take power.