God wants everyone to be saved! 2 Peter 3:8-9  

However, because of His justice, God can only save those who obey him! Matthew 7:21

Obviously, one must hear and believe the Gospel message. Romans 10:14-17

One must confess that Jesus is Lord. Romans 10:9

One must repent of his/her sins.  By the way, repentance is much more than just sorrow.  A lot of folks are sorry that they "got caught," and sorry that they hurt others.  True repentance is being sorry AND changing one's behavior.
Luke 13:1-9

One must be immersed (baptized) for the forgiveness of his/her sins. Acts 2:38

All of this, however, is just the BEGINNING!  The walk with Jesus is just starting.  Now one must find a congregation of believers who are following as accurately as possible the pattern established in the New Testament, and meet with them regularly. Hebrews 10:25

The Christian must pray every day and read and study the Bible.  He/she must fight every minute to avoid giving in to the devil's temptations.  He/she must, in some capacity, share the Good News of Jesus with others.  In the end, our obedience and God's wonderful grace will take us to Heaven!