There are many different approaches to the Book of Revelation, but we will only deal with the approaches you are most likely to encounter.
Preterist: The book primarily deals with things that have already happened. This view is held by Amillennialists who are mostly Calvinist or Reformed,
Futurist: The book primarily deals with things that will happen in the future. This view is held by Premillennialists and is the view with which you are probably most familiar