Revelation 4:1 - "After this I looked, and, behold, a door was opened in heaven: and the first voice which I heard was as it were of a trumpet talking with me; which said, Come up hither, and I will show thee things which must be hereafter."
Revelation 7:1 - " And after these things I saw four angels standing on the four corners of the earth, holding the four winds of the earth, that the wind should not blow on the earth, nor on the sea, nor on any tree."
Revelation 7:9 - "After this I beheld, and, lo, a great multitude, which no man could number, of all nations, and kindreds, and people, and tongues, stood before the throne, and before the Lamb, clothed with white robes, and palms in their hands."
Revelation 11:11 - "And after three days and an half the Spirit of life from God entered into them, and they stood upon their feet; and great fear fell upon them which saw them."
Revelation 15:5 - "And after that I looked, and, behold, the temple of the tabernacle of the testimony in heaven was opened."
Revelation 18:1 - "And after these things I saw another angel come down from heaven, having great power; and the earth was lightened with his glory."
Revelation 19:1 - "And after these things I heard a great voice of much people in heaven, saying, Alleluia; Salvation, and glory, and honor, and power, unto the Lord our God."
Revelation 20:3 - "And cast him into the bottomless pit, and shut him up, and set a seal upon him, that he should deceive the nations no more, till the thousand years should be fulfilled: and after that he must be loosed a little season."
In addition to these verses showing that the Book of Revelation has a time-line, there are twenty-four verses that contain the words "And I saw" (Rev. 5:1, 2; 6:1, 2; 7:2; 8:2; 9:1; 10:1; 13:3; 14:6; 15:1, 2; 16:13; 17:3, 6; 19:11, 17, 19; 20:1, 4, 11, 12; 21:1, 22).
Knowing that Revelation is sequential, helps the Bible student to understand that the Rapture (pictured in Ch. 4:1); the Tribulation (Ch. 6-18 - with the Mid-Tribulation Abomination of Desolation being found in Ch. 13 as per Dan. 9:27 and Mt. 25:15); Christ's Second Coming (Ch. 19); Christ's Millennial Kingdom (Ch. 20); and the New Heaven, New Earth, and New Jerusalem (Ch. 21)!
"Blessed is he that readeth, and they that hear the words of this prophecy...."
"Blessed is he that keepeth the sayings of the prophecy of this book."
(Rev. 1:3 and 22:7)!