Wow. What a question. I wish more people would wonder about this. The truth is most people spend more time planning for their retirement which pales in comparison to the time frame of eternity and where they will spend it. I personally believe that to be "saved" you must put your complete trust in Jesus Christ as your Savior and at the same time turn from (repent) from the life you have been living. Now you might be offended by me insinuating that you have not been living a "good" life. The truth is we all have not lived a "good" life. If you compare your life to others you might say, "Well, I haven't killed anyone or I haven't stolen anything or raped anyone and compared to people who do those things I am a pretty good person". That's what happens when we compare ourselves by ourselves. The problem with doing that is that we are all flawed. There has only been one person who lived that we should compare ourselves to and that is the life of Jesus Christ. Jesus said that there was only One that was and that was His Father in heaven. The truth is we have all broken God's law. Have you every stolen anything (regardless of it's value)? If you have you are a thief. Have you ever taken God's name in vain? If you have, that's called blasphemy and is a very serious offense. Have you ever told a lie? Sure, we all have. That makes you a liar. You might say well I don't do any of those things any more or that often. Ask yourself this, How many times do you have to kill someone to become a murderer? How many times do you have to rob someone to become convicted of robbery? The answer is once to both of these questions. If you are consistent you will see that you only need to break one of God's laws to be found guilty before Him and the bible says that all will have to stand before Him and give an account for their life. When you stand before Him you will be found guilty because we have all broken his laws (10 Commandments). When we break His law the bible calls this sin. Because He is a good God and a just God he must punish sin. It is not God's will to punish you though. That's why He sent His Son, Jesus Christ to die on the cross for you and take your punishment upon Himself. He loves you and wants you to be with Him in heaven for all eternity. You must put your faith and your trust in Jesus Christ though. That is the only way. He is the only one that could pay for our sin because he was sinless. Jesus said that He was the way, the truth and the life and that no one comes to the Father except through Him.
There is a short movie clip that you should watch that I have posted the link to. I think it might help explain what I have been trying to say a little better. I pray you find the Truth of how to be saved.