I've found the following background to be helpful:
The Revelation is believed to have been penned by the apostle John, who in his later life was stationed in Ephesus and served as overseer of seven churches in Asia Minor. It was written at around 95 A.D. from Patmos Island, a barren prison colony on the Aegean Sea where John was exiled for his faith.
The end of the first century was a time of great tribulation and stress for Christians. The emperor Domitian demanded that everyone pledge supreme allegiance to him as lord and god, and many who refused to do this faced martyrdom as a result. The letter was meant to encourage and strengthen believers who were going through persecution, and the use of a kind of code language may have been deliberate.
Type of Literature
The Revelation, unlike most of the Bible, is in the genre of apocalyptic literature (like parts of the books of Daniel and Ezekiel) and is thus far less familiar to us than it was to first century readers. With their familiarity with this kind of writing, they would have more readily sensed what these collages of word pictures and images might mean.
Here are some of the distinguishing characteristics of apocalyptic writing:
1. It represents a message to be written, and then read and spoken, rather than being a collection of prophetic or poetic messages that were first spoken orally, then written.
2. It contains visions of dramatic and cataclysmic scenes--of conflicts, judgments and suffering, of cosmic behind-the-scenes struggles between forces of good and evil, and of God's ultimate and final triumph.
3. It is highly visual and visceral, with repeated references to "I saw...". "I heard...", and to experiencing such things as incense, sulfur and smoke one can almost smell.
4. It employs a lot of symbolic code language and "political-cartoon-like" images
living creatures, angels, radiant woman, elders, thrones, crowns, stars, lamp stands
serpent, dragon, false prophet, Babylon, the great harlot
beasts, eagle, bear, lions, horses, Gog and Magog, Armageddon
• 3, 4--and especially 7--suggest wholeness, completeness, harmony, the number of God
• 6 and 666 (or 616) represent what is evil, false, deceptive and counter to God
• 12 seems to represent the people of God, under both covenants
• 3 1/2 years (42 months, 1260 days) suggests a half way point in time
• 1000 suggests a vast number, or a very long time
(so 144,000 could represent the full number of God's people, 12 x 12 x 1000)
5. Like other prophetic texts in the Bible it had immediate relevance to its contemporary readers, while also revealing patterns that are repeated and are being fulfilled today and in every age.
Here's a link to another post that shows just how relevant the Revelation is for today.