I believe the Party uses technology mainly as a way to control its citizens. It does this by using technology for surveillance and for propaganda.
The main image of technology in 1984 is, to me, the television screen. These screens are two-way things that allow some one to watch everyone who has a screen all the time. We also know that the Party can plant microphones in various places. If you never knew when the Party was watching you or listening to you, I would think that would control you a lot.
The Party also uses the screens and movies for propaganda. It uses them, for example, in the Two Minutes Hate. This sort of use affects the way people think. That helps the Party control them as well.