Well, there are many many entities that help teach and refine this. Gabriel, Azazel, Mepsitahl, to name a few. Erlathus, who is known by humans as the Black Sun(in the Qlipphoth) is the one that taught me, and several friends of mine, in sensing energy.
BEsdies working with him,meditation,psionics, energy manipulation, all can help one become more aware of energy. For psionics feel free to look up the work of Uncle Chuckie and for energy manipulation, Omnimancy.com.
In terms of clairaudience, open a sigil, or use some other form of mentally connecting to a spirit, in order to learn how to hear them. Prepare 12 questions beforehand. Simply open the sigil/establish the connection and while still in the trance ask the questions. Write down the first thing that comes to mind, the first line of thought that comes.
This is to eliminate doubt. In every moment, be sure that this is real.
For clairvoyance, practice scrying.
Also, Konstantinos has various exercise in his book, the Art of Summoning Spirits.