A psychic detective specializes in following psychic connections.
The most important concept for a psychic detective is 'psychic energy signature'. You may think of energy signature as the most defining quality of something or someone. When you think of something, the first thing that pops into your (subconscious) mind is that thing's psychic energy signature.
Energy signature is how the psychic detective tells apart one thing from another. The psychic detective is an expert at looking at a big knot of psychic energy, telling apart the different energy threads it is made of, and following the thread he or she is interested in.
By following the energy signature of a psychic thread, the psychic detective can tell what kind of connections and interactions that psychic energy makes, and the resulting patterns can be recognized in the 'normal' world as well.
A psychic detective is good at discernment and deduction, and is wary of making unnecessary assumptions.