If you are interested in becoming a spirit worker proper preparation and trained teachers are necessary and can skillfully guide you on these journeys. You should expect your teachers to make sure that you are becoming skilled at rhythmic breathing, grounding, shielding and saining or smudging. These must become second nature before any type of ritual possession is practiced, light or full it doesn't matter proper training and preparation are important. Lastly you may find that after working with spirits from the other side you own energy changes. This is to be expected as journeying to another realm or having spirits from the other side visit you will change the energy in the room, and your body, just remember like attracts like. Countering these energies with rituals cleansing, baths, and meditations that focus on the opposite type of energy will help keep you balances.
This is not a practice to be rushed and many spirit workers spend years in intense training so they can navigate the dark highways of the other world. Always use caution, and anytime you work ritual possession or spirit work, make sure to have an experienced guide or ward to watch over you and is able to retrieve you if need be.