Meditation on the Master
Your best method is to concentrate on the Master as a Living Man inside you. Make his image in your heart and a focus of concentration so as to lose all sense of bodily existence in the one thought.
During concentration, one must make oneself as positive [resistant] as possible to spooks and all astral lower influences, but as negative [receptive] as possible to the influence of the Master.
The idea of the Master will prove the best influence against spooks, etc. The effort is far more dangerous for psychics than for others because their bodies are much more sensitive and attract more various other powers of nature.
Spooks and astral influences act through the physical man on the astral body . . .
Every one of you create for yourself a Master. Give him birth and objective being before you in the Astral Light. If he is a real Master he will send his Voice. If he is not a real Master, then the Voice will be that of the Higher Self.
Everyone will receive according to his own inner merits and development.
“Concentration and Union with the Higher Self”