Earlier I was thinking that this was an idle question, and if so, it really is a dangerous one, because you may find the pleasure that people find in horror movies, only for real, and that is a quick path to real problems with real demons. You may find yourself the patient that way. It is not for the idly curious.
I left it at that for a while, but then I was thinking. What if it is not an idle question? There are people called to this ministry, both to be “in the room” and to intercede somewhere else. You may be called to this, but it will not be for the sake of the excitement but for the sake of the One who calls people and gifts them. Like a doctor loves to see people healed, you may love to see people set free from oppression.
So, let us say you are called to that. What does it take? A pure and a stout heart, the gift or faith, the ability to pray at length and shut everything out except the Lord. How do you get there? Get good at the basics: prayer, living rightly, taking the Sacrament. You know the drill; excel at it. Spend time in church alone before the Lord. I mean hours, on a regular basis. Put up a crucifix and meditate on it. Fill your heart and your mind with Scripture and shut out worldly things. Consecrate your life to Jesus. Live in faith. Get a good spiritual director.
There is a real need for prayer warriors, for people who “will stand in the gap” in this particular ministry. But then, this is good for any ministry, for wherever the Lord calls you. “Here I am, send me!” should be the cry of the Christian. And some He sends into very dark places, very dark places indeed. Only if your eyes are fixed on His light will you be able to see. And what happens at an exorcism is incidental to the reality that the King of Kings and the Lord of Lords is supreme over every power, and every knee will bow and every tongue confess that Christ is Lord.