I have seen people healed through prayer.  Miraculously.  I remember a young child who was in the last stage of dying from cancer.  I was at the hospital with his mother, who was in a class that I taught.  We were waiting by the child's bed for him to take his last breath, when she begged me to pray for him that he would be healed.  I did.  But I didn't feel like it was going to happen through my prayers alone.  I called a friend of mine, explained the situation and asked her to pray as well.  She was a real "Prayer warrior."  She then called everyone she knew to start praying.  Probably over fifty people.

The child got better.  He lived to his teens.  There was no doubt that God answered the prayer.  But there have been other times that the case came out differently.  I don't think someone can say, "I'm going to pray for this person to be healed and if I believe they will be healed (name it and claim it) then they will be."  It doesn't depend on how much faith you have.  It depends on God.  He decides.
How little, or how much faith you have is not the issue.  There is nothing wrong with you.  You don't have to "Rev up your faith" to get God to listen.  If you are a Christian, you simply go to God and ask--knowing that He will intervene if it is in accordance with His will.  He does hear us.

Even Jesus had a healing "difficulty."  It certainly wasn't due to Jesus' lack of faith.  Jesus had total and complete faith in the Father.  In Mark 8: 22-26, a blind man was brought to Jesus.  His friends asked Jesus to touch him.  Jesus took him out of the village (away from the public view) and spit (!) on his eyes, put his hands on him, and asked the man if he could see.  The man answered and said," I see men that look like trees walking."  (I don't see clearly.)  So Jesus put his hands on the man's eyes again, and told him to look up.  He did and was healed.  (Read Keith Miller's "A Second Touch.)

Was it the spit?  Was it Jesus' hands?  Was it because Jesus touched him a second time?  Or was it because the man looked up?  Is there power in the method used?  Of course not.  Otherwise we would all be telling people to "Leave town.  Let me spit on you.  Now, I have to touch you twice--once won't do the job.  After that, you have to look at the sky and then you will be healed."   That would be the Church of "leave town, spit, touch twice, and look up."  The method is not the reason the man was healed.  Jesus didn't use a programed "method."  Sometimes God gives us what we ask for.  The secret is that you need to ask.  There are a number of incidents in the Bible where God changed His mind about something.  Why?  Because one of his children asked. That's when God decides.