What are the two aims of the Party?
The Party is a geo-political machine that has many roles, depending on the ministry. The Ministry of Truth spreads fear through propoganda. The Ministry of Peace wages war to enlist patriotism. The Ministry of Love ferets out and tortures rebels. The Ministry of Plenty rations materials in the name of equality.
If one were to limit the aims of the Party down to one aim, it would be to quiet the mind. One cannot rebel physically if one cannot conceive it first mentally: thoughtcrime. Quieting the mind can be done two ways: censorship and uber- patriotism.
Orwell's greatest fears of the extreme left (communist U.S.S.R.) and the extreme right (fascist Nazis) were essentially the same. They burned books before they waged war. They quieted the minds within the country before they invaded other countries. The easiest freedom to limit for both parties was speech. The easiest way to not only limit a party's existing critics but its future generations of critics is to control a people's language. Get rid of books and open press; strike entries from the dictionary; replace old words with new, utilitarian ones.
After language has been limited, the mind must be preoccupied for activity for the party in the form of uber-patriotism. In order to breed weak-minded workers, the Party must run society like a military machine, with slogans and rations and group exercise.