How did 20th Century dictators create totalitarian governments?

With its rapid overthrow of democracy, and its creation of an all-powerful new leader figure in the form of Hitler the Fuehrer, many have seen the Nazi regime as the archetypal totalitarian state. Nazi Germany was certainly more totalitarian than Fascist Italy. Its powerful propaganda seemed to successfully mesmerise the masses, while its political police, the Gestapo, controlled all aspects of thought within the regime. The reality of course was far more complex. While powerful, propaganda was often seen far more critically in Germany than many first supposed. The Gestapo was also far less well resourced than the mythology suggested. Finally, the leader himself was often disconnected from decision-making and could be manipulated by those around him.