How can I know for sure that I am on my way to heaven?
Realize that God loves you.
John 3:16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
Realize that everyone is a sinner.
Romans 3:23 For all have sinned, and come short of the glory of God;
Realize that sin has a price that must be paid.
Romans 6:23 For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.
Realize that Jesus Christ died to pay your price.
Romans 5:8 But God commendeth his love toward us, in that, while we were yet sinners, Christ died for us.
Finally, pray. Ask Jesus Christ to be your Savior, and claim His promise of eternal life.
Romans 10:9 That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.