A number of believers have asked me over the years how I prepare before going to minister healing. Sometimes I will pray for a few minutes at home before heading out, but that's combined with a lifestyle of prayer. I don't pray for hours everyday, but I do pray throughout the day, everyday. I can do nothing without Him and I've noticed the positive effects of prayer, even before heading out to minister. The bible shares several accounts of prayer before ministering healing, including when Paul was on the Island of Malta.
Acts 28:7-8 shows this truth.
There was an estate nearby that belonged to Publius, the chief official of the island. He welcomed us to his home and showed us generous hospitality for three days. His father was sick in bed, suffering from fever and dysentery. Paul went in to see him and, after prayer, placed his hands on him and healed him. - Acts 28:7-8