Meditation or will
The shamanist shifts into the alternate reality of thought, form, and energy by moving their center of focus. The physical body of the shamanist may or may not remain in the original location, but the mind and spirit of the shamanist moves to a state of altered consciousness. This is commonly practiced by the Western world under the guise of “psychic abilities”.
Physical or sensory deprivation
The shamanist undergoes fasting, no sleep, and darkness. The focus of all of these is to remove the outward contemplation, turn thought inward toward another reality. The removal of the outward world provides a clear and open pathway to other realms of thought and energy. Dreaming is a very mild example of the transition achieved in these states.
The use of sacred plants
Culturally accepted mind/mood altering plants are used for sacred reasons, not recreational. Often, when there is a mental narrowness that impedes the achieving of non-ordinary reality, the sacred plants open the door and provide a entry. Future entry can then be achieved through other means.
Auditory aids to altered states
Drums, chanting, and music serve the purpose of bypassing the logical, language side of the self. It is known that the auditory aids activate all brain centers, opening states of consciousness suppressed in ordinary conditions. Drumming is a common tool for opening the shamanist to journeying.
These represent a combination of logic and intuition as man reaches for symbols of a unified order of things. The spirit allies can be part of ourselves, and also part of that universe outside of our brain. Engaging spirit allies is like strapping on an auxiliary form of transportation. The shamanist is aided in their travels by an energy that is perceived to be outside of themselves.