Several aspects of Marxism seem relevant to 1984. Marx saw all of history as a struggle between the classes, culminating in the workers of the world uniting and creating a stateless, classless society in which the people owned the means of production and shared the profits to create a society of plenty for everyone.
Clearly, Oceania is very far from the ideal socialist state as envisioned in Marx. It is essentially a fascist state, if we define fascism as a form of government with a supreme leader and his small group of followers having close to total power, a lack of democratic institutions, no freedom of speech, and a powerful secret police force dedicated to crushing dissent, all aimed at keeping the country in constant state of war-readiness.
If Marxists saw fascism as embodying, in the words of critic Irving Howe, "a final decayed form of capitalism," we might look at how, through a Marxist lens, the inner Party props up its power: is it through promoting worship of Big Brother, propaganda, and terror? Why, from a Marxist point of view, does Oceania tolerate such a large population of seemingly unemployed or under-employed proles? Is it to have a surplus labor pool to keep labor costs down? If Marxists understood the lowest class of society as the group that would rise up and take power, is Winston right in believing the proles are the hope for the future?
I would suggest looking at Party propaganda and the proles through a Marxist lens as a starting point.