What is a prayer offered in faith?

And the prayer offered in faith will make the sick person well; the Lord will raise him up. If he has sinned, he will be forgiven.
James 5:15

Does this phrase ‘prayer offered in faith’ mean that we should wait until we have some sudden or great influx of faith that assures us so mightily of an imminent miracle that we have to do nothing but stand and wait for it? Or, on the other hand, do we speak out whatever is the prayer of faith when we have understood that Jesus helps and heals today and that we have authority over unwanted things in our lives?
If we then speak the words ‘Be healed!’ Or ‘be gone!’ will it happen for us? We may look very foolish if it does not! How do we pray an effective prayer of faith? How do we do the works that God intends us to do? We should forget what is in our minds and consider what is in our hearts. In John’s Gospel we find the followers of Jesus facing the same misunderstandings. Jesus told his disciples that the work of God is to believe in the one he has sent (see John 6:28–29). In other words, we can be used by God, through the power of the Holy Spirit, to work miracles if we simply believe that Jesus did do it, that he can do it and that he will do it. If we trust enough to rely totally on him then we begin to pray in faith, whatever the form of prayer we use.
But how to deepen our trust? One most important way is to move more deeply into the heart knowledge that Father God wills an abundant life for everyone.
do we have to believe if we want to pray the prayer of faith and heal the sick as did Jesus and the apostles?
So the fuel for the prayer of faith is our believing that Jesus, by doing miracles, is showing us the ‘heartbeat’ of God.
Amazing things will start to happen if we really get this under our belt: that the heart of God is to see everyone who comes to him helped and healed.
There is no particular method of praying—no prescriptive answer—only a compassionate ache for those who suffer and a concrete trust in the will of God to help.