With the other books of the we first read the book to determine the date, so determining the date first to understand Revelation is kind of like putting the cart before the horse.
A few of date indicators within Revelation include John being requested to "measure" the temple and those that worship in it (11:1), indicating that the temple was not yet destroyed at the time of the vision, ie before 70AD.
The 2 witnesses in that chapter also prophesy in Jerusalem "a thousand two hundred and threescore days".
Jerusalem is identified in v.8, and in the passage appears to be populated and not yet destroyed.
Having identified the "great city" of 11:8 as Jerusalem, we already have the identity of the harlot in chapter 17.
We are told a great deal about this harlot, and it would be difficult to miss her identity.
The harlot seems alive and well as she sits on the beast (17:3), and the relationship between the woman and the beast has not yet become openly hostile.
This beast is identified as Rome in 17:9 by the seven mountains, but John seems to hope that mainly Christians will understand this identification, ie "the mind which hath wisdom".
In 17:16 John also predicts the Roman destruction of Jerusalem as future.
I have only covered these two chapters, because they are fresh in my mind from a recent conversation with
@OMC, but the whole book is full if similar date indicators.
We could of course consider the possibility that Revelation was written after these events, explaining the past rather than predicting the future.
If we were discussing Moses writing Genesis that would be the case, but with Revelation I doubt it.
We are told that the book is about things that must shortly come to pass, not events of the past.
For people interested in exploring this view of Revelation I will also post a sermon by Chuck Baldwin.
At this point in time I find no reason not to endorse the things said in this sermon: