what methods are used to easily keep the proles in control?

I think keeping them ignorant is an important one. The Proles pretty much are left alone. The Party seems to appeal to their baser instincts by giving them pornography and the lottery. They are kept ignorant though a decided lack of education. The Proles do not revolt because they simply don't know any better. Children, sex, alcohol, minimum of food...are all there to keep their little minds occupied. Hey, that's kind of like us!

Besides the lack of education, the Proles are kept in continuous shortages, so that a small supply of cheap cooking pots is a big deal to them. When people struggle just to survive, the bigger ideas like freedom are not important.

The "war" is another control mechanism. The occasional bombs serve to destroy parts of the Prole districts, making survival more difficult, plus then the Proles believe that they need the Party to fight off Goldstein.