Establish a steady pulse. Like a heartbeat, trance music has a steady pulse which does not slow down or speed up. Play the drum (with your hands or with drum sticks), in a steady, unchanging pulse like a regular heartbeat or walking rhythm.
Add subdivisions of the beat. For each pulse-note, you can play two, three, or four equal beats. Vary these rhythmic subdivisions to create rhythmic interest and new patterns.
Repeat your beat patterns several times. Trance music works on repetition, so keep an individual rhythmic pattern going for some considerable time before moving on to a new or different pattern. The underlying pulse of the music stays the same throughout.
Use dynamics (getting louder or quieter) to change the mood of the drumming trance music. This in turn will affect the mood of the shaman or listener.