Question: "How can I be ready to be caught up in the Rapture?"
Answer: It is much simpler than you may think. The short answer is that you must receive Jesus Christ as your Savior. Now for the long answer. When you ask this question, we assume that you have heard that not all Christians will be taken when the Rapture occurs. You probably have been told that only "super Christians" who are living a holy life will be raptured, and all the other Christians will have to suffer through the Tribulation. This is not true, and we will show you why this is not true from Scripture.
The first thing that you must understand is the purpose for the Tribulation. The Tribulation is a time of judgment on the earth and punishment for Israel. Please note that Israel and the Church are not the same group of people. The Church is a spiritual organism. People in the Church are related because of their spiritual birth (by being born again - John 3:3). The people of Israel (Jews) are related by blood. This is a race of people to whom God made special promises in the Old Testament. God declared a time of judgment upon Israel for their unfaithfulness. This time of judgment is clearly declared to be only for Israel (Daniel 9:24-27).
Gabriel brought a message from God to Daniel (9:20-21). Daniel 9:24 says, "Seventy weeks have been decreed for your people and your holy city, to finish the transgression, to make an end of sin, to make atonement for iniquity, to bring in everlasting righteousness, to seal up vision and prophecy, and to anoint the most holy place." In this message Gabriel specifies to Daniel that the time is "for your people." Daniel's people were Jews, the nation of Israel. God declared 70 weeks against the nation of Israel. This “70 weeks” is literally in the Hebrew “70 sevens.” In other words, 70 times 7 years, or 490 years. Of those years, 483 (69 times 7) of them were fulfilled from the end of the Israel's captivity in Babylon to the cutting off of Messiah (the crucifixion of Christ). This leaves 7 years of judgment yet to be fulfilled. Those 7 years are the years of the Tribulation. The point is that this prophecy concerns Israel primarily, and the purpose of the judgment is "to finish the transgression, to make an end of sin, to make atonement for iniquity, to bring in everlasting righteousness, to seal up vision and prophecy, and to anoint the most holy place."
Now, we can also demonstrate from Scripture that Christians will not be in the Tribulation. A study of 1 Thessalonians 4:13 through 5:9 shows this. In this passage Paul writes about the Rapture and the Day of the Lord. First Thessalonians 5:9 gives Christians this promise: "God has not destined us for wrath, but for obtaining salvation through our Lord Jesus Christ." Pay close attention to this verse. Paul says God has not destined us for wrath, specifically the wrath of the Day of the Lord (5:2).
Further evidence that Christians will not go through the Tribulation comes from 1 Corinthians. In that letter Paul sharply rebukes the believers for being carnal Christians. But in chapter 15, Paul writes of the Rapture, and he never indicates that any of the Corinthian believers, carnal though they were, would be left behind. True believers in Jesus Christ will not have to endure the Tribulation.
The only way you will be left behind in the Rapture is if you have not received Christ as your Savior.