First I think you have to define 'paranormal'.
Do you mean experience something out of the norm (for you)?
Do you mean experience a tangible, objective change in reality?
Do you mean experience a mental or perceptive change which may not be objectively verifiable?
Or do you mean experience the pop culture definition, i.e. 'see ghosts', or aliens or spirits?
There are a couple ways to experience a subjective 'extra-normal' event, and that's commonly done by deprivation, usually sensory dep.
(
isolation tanks spring to mind).
Other ways involve trying to change the brain chemistry, or brain waves. Some involve just making transitory changes in the physical milieu.
Extremes of temperature, pressure and changing other aspects of the environment can cause unusual reactions.
One common method practiced by Native Americans is the '
vision quest'. Here sleep deprivation,
dietary manipulation and experiencing novel environments are used to allow mental effects to surface.
One of the easiest methods is changing the diet - specifically fluid fasting is used. This causes distinct changes in brain chemistry which is
probably the root of most 'paranormal' events however I like to call them 'extra-normal', since anything that happens in nature -is- normal. IOW,
how can nature truly be 'para'?
IME, CCK is one of the most potent modifiers of sensory and physical sensation, but it may not effect everyone the same way.
Due to T&C, discussions of plants and chemicals is beyond the scope, and I find them to be less useful than diet and physical methods for the most
part. IOW, things that you cause to be different using non-chemical methods seem more 'real'. YMMV. HTH.
2 cents.
PS posting this does not mean I'm advocating any methods, since these can be hazardous. Don't try this at home, etc.