To fully appreciate the Psalms, we should read them according to four perspectives. Not every Psalm contains all four of these perspectives, but a surprising number do and virtually every Psalm can be read from multiple perspectives. Using these perspectives helps us to recognize just how much is in each psalm.
Understanding the main themes of the book of Revelation is critical to studying the book. Most people assume the main themes of the book are subjects like the Antichrist and apocalyptic trouble. These certainly are themes in the book, but they are not the main themes. We must know the main themes in order to approach the book correctly.