What are the different ways that the Party obtains and maintains power in Oceania? Which is the most potent?

In the novel, 1984, we are presented with a futuristic dystopian society. Where a single party government is in control, which is called "The Party." The Party is oppressive, and maintains complete control over all aspects of its citizens by instilling a fear that "Big Brother" is always watching, through "Doublethink," and by "Newspeak." Of all three of these, Newspeak is the most effective because what Newspeak entails is the constant changing/updating of language that majorly disrupts people's ability to completely understand the most recent language even with the dictionaries that are published because of each new version of the language, and if people cannot effectively communicate with each other, then there is little chance of rebellion.