Was it just a lucky guess? Orwell's Oceania can be a bit considered to todays real world. How did Orwell do it?

I think these
answers are covering it, but allow me to add one point. Depending how general you wish to make
connections about similarities, you could easily draw connections, and here's why:

One thing that does not change is that people can be dissatisfied. There is always
going to be something that people will be unhappy about, and those people might use exaggerated
terms to describe the problems. So, for instance, you might hear someone called a Nazi, when in
fact, they are no such thing; the term is used to show displeasure about something.

It's easy to draw connections to things if you look...