Evil Spirit and unwelcome communication is a common concern and frightening fear when one begins a journey of psychic development. It is important you address these fears early on so you do not harbor negative energies and self-doubt. I found a passage by Raymond Buckland I feel is helpful in addressing those fears.
“Like attracts like” is the adage, and it has proven to be true. For this reason, you really need have no fear of attracting to you evil entities of any sort, while practicing your mediumship. Yet this is certainly a common fear among newcomers to Spiritualistic phenomena. Indiscriminate use of items like Ouija boards has brought problems to some people in the past, which has helped give rise to this apprehension. But, as I say, like attracts like. In other words, if you’re the sort of person who is positive, seeking to help others through your mediumship, and looking to advance spiritually, then you’ll attract nothing but good to you. You really have nothing to fear. On the other hand, if you are the sort who takes delight in playing pranks with a sadistic twist to them, are not averse to swindling people out of their savings, and wouldn’t think twice about dealing in stolen goods, then you might well draw similar spirits to you! And along with such negative spirits you might well attract negative “entities,” for want of a better term; elemental beings from other realms who might be looking for a means of entry into this one. Ivy Northage (previously quoted) says:
I am often asked If psychic activity invites evil spirits. Accepting a reasonable and sensible approach to all such phenomena, the answer is a positive no. Like attracts like, and someone sincerely desirous of developing their gifts for the good of humanity cannot be in touch with evil. It should be remembered, however, that psychic ability on the astral level is as a light in a foggy street. Therefore, uncontrolled or denied the spiritual stimulus of upliftment afforded by the guides, it can expose you to mischievous or lost spirits that, once attached, can be difficult to dislodge without firm refusal of psychic activity on the part of the medium.
With all of this in mind, it behooves the sensible medium always to take some precautions just in case. It takes but a moment to erect a psychic barrier around you, so why not do so every time you prepare to do any sort of psychic work? And I would even include your meditation. Here is a simple little cleansing and protection process you can go through right before you meditate, right before you try table tipping, psychometry, automatic writing, or a full-blown séance. In other words, every time.
Sit quietly for a moment, eyes closed, feet flat on the floor, hands loosely in your lap or on the arms of your chair. Breathe deeply and evenly, and calm yourself. Then, as you breathe, imagine that with each intake of breath you are drawing into your body the soft, positive, blue light of protection; as you breathe out you are pushing out all negativity. Feel this blue light (some people prefer to “see” a white light or a golden one; use whichever color you feel most comfortable with) coming up into your body through your feet. Feel and sense that it is coming up from “Mother Earth”; from the great goodness of nature. Even if you are sitting in a room several floors up in a building, you can still sense this energy coming up out of the ground and then slowly climbing up through the building until it reaches your floor and your feet. Look upon this as an attunement with nature and with all the positive aspects of the myriad forms of life in and on the earth.
As you breathe in and out, feel/sense your body filling with this positivity and driving out all the negativity until you are completely filled with good energy. Then keep going for a while. “See” the light expanding until you are totally enclosed in a sphere of it; a ball of light with you in its center. This is your protective shell. This is the egg of which you are the yolk. Nothing negative can break through it. Know this, and accept it. It will serve and protect you.
If you are of an especially religious turn you might want to add the saying of a prayer to this practice. You can do this as you work on the power/light building. Another alternative is to see white, gold, blue, or whatever color light descending from “above” (from God/Goddess/All That Is) and entering your body at the crown of the head or the position of the third eye, rather than coming up from the ground.
Do not hesitate to do anything that will give you an added sense of security and protection. But at the same time don’t, please, scare yourself into believing that you are about to embark on a perilous journey that is fraught with danger and from which you may not return! As I said earlier, there is probably no need for this protective measure at all; we are just doing it to err on the side of safety. So do it as a matter of course, then carry on without thinking anything more about it. You will be fine.