Not many mediums, in my experience, like to give a spirit reading without giving time and thought to it. They have to prepare. Not all mediums use the same techniques but most prepare. It may even be a sort of ritual.
Some like to meditate before tuning in to the spirit world. Others may like to pray. Some like to tune into their spirit guide and ask for their help.
Personally I like to pray and ask for my guides to come close and work with me. I ask them to allow my sitter’s spirit loved ones to come through and bring them some proof of survival.
I tune in to a higher level of consciousness so that I can work with spirit. By the time my sitter arrives I am well prepared to give the reading.
During the reading I communicate with my sitter, my guide, and the spirits. There is usually a 3 way conversation. It can become rather complicated at times but if I stay with the higher level of consciousness it works out well.
When my reading is over I always ask spirit to use up any left over energy as healing.