"Confess your trespasses to one another, and pray for one another, that you may be healed. The effective, fervent prayer of a righteous man avails much. Elijah was a man with a nature like ours, and he prayed earnestly that it would not rain; and it did not rain on the land for three years and six months."    

James 5:16-17

The righteous man is the one resting in Jesus; the one who relies on the finished work of Christ, and not his own.  The one who recognizes they need Jesus to be right with God.  This is a righteous man!  The fervent prayer of this man will be effective because he will pray the will of Jesus and not his own.  This man will pray in the name of Jesus, and will see his prayers come to pass because he seeks not his own will but that of his Masters.

Elijah prayed according to God's word and not his own will.  It was not Elijah's idea to stop the rain from falling, and then to have it fall again, it was Gods.  Elijah as a righteous man only sought God's will to be done here on earth and it was.  As we pray according to the will of God, relying on Jesus Christ we will see the power of Heaven released upon this earth, and our prayer life will be fruitful!

"The LORD is far from the wicked, But He hears the prayer of the righteous." Proverbs 15:29