This is the most difficult part of your reading! There is no set way to choose a psychic. However, knowing what the psychic does is helpful. A clairvoyant or clear seer, sees images. Your reading will contain imagery that needs to be interpreted.
Someone who practices Psychometry will need an object as they obtain vibrations from physical objects. A clairaudient hears voices. A medium or channeler allows another entity to take control of their voice and give messages. They are not in control of what is said. A Tarot reader, interprets the tarot cards for you. The same is said of a Rune Master. So, which to choose?

First try to find someone compatible with your philosophy or religion. Then you may wish to choose someone with similar life experiences. With clairvoyance and the other soft mediums of divination, experience may not be relevant. But with Runes, Tarot and Astrology, experience and study are needed. Check credentials.

Use common sense. If someone offers you a palm reading by phone, you should be wondering how they can see your palm. If an astrologer doesn't need your birth date (and they aren't doing Horary astrology based on the time of the question) you should wonder. If someone offers an astrology reading based on cards, you should know it is a form a cartomancy (diving the future with cards).  If someone promises something unreasonable, you should be wary.

And last, use your innate psychic ability and choose someone you are drawn to for a reading.

Trust us, price is not a measure of ability.