How does one test the spirits and identify false preachers?

The Word of God says, >Dear friends, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world (1 John 4:1) Many televangelist claim miracles happen and profess the name of Jesus. Some have claimed they witnessed terminally ill people get healed and such. There have been some high profile preachers from around the world who have been accused of staging miracles and preaching the "gospel of prosperity" for their own gain. What is the way to test whether they are false prophets taking care not to touch the Lord's anointed? I went through [a similar post](https://christianity.stackexchange.com/questions/8074/how-do-we-identify-false-teachers) , but am concerned with teachers who say they are doing it in the name of Jesus.