How do I open my mind to the spirit world?

The approach to the spiritual world is closely guarded—extremely so, as I have recently discovered, and when you are not in rapport with the higher spiritual entities, you are in extreme danger of coming in contact with spirit lives of a much lower order, some of which have all the appearance of being demented.

I have recently while in the midst of receiving beautiful thought impressions and information from the spiritual world come suddenly in contact with malicious and evil influences and spirit lives, and have been greatly frightened and forced to draw back with all the caution of one who momentarily expects an attack. 

And I would warn you—one and all—of the dangers of approaching the spiritual world, even if you are able to do so, until you have made long and special preparation, for there is danger here of a nature, which you do not understand and of which I am not able as yet to fully inform you.

Fragments of Spiritual Knowledge Pertaining to the Spiritual World,