One thing that may not be obvious if talking about spirit interactions and how to become aware of existences beyond the regular, is not an "exercise" as such, but rather how to improve your body state. I haven't posted about this earlier because I was unsure about how effective this is, but I can say now that there are ways to speed up the cleansing and development of your soul/karma/mind/body using material substances.

For some the effect is almost instant, for some it's having an effect on your constitution overall which naturally activates your ability to remove the bad substances/energies from your body on all planes.

What I have used:

Fish oil, improves functioning of the brain and eyes
Magnesium, improves nerve function
Orange (or any suitable fruit) juice, vitamin C from a natural source is the better choice compared to supplements
Beetroot juice, improves oxygen uptake
Ginger, can prevent migraine, nausea and stomach issues
Nettle or Senna leaf tea, cleansing of the gut

These are mostly natural substances with weak effect, this is intentional; you want to trigger a natural improvement and cleansing, not force it using drugs.

A note on the nettle and senna leaves is that you should not use these regularly. If you do you will instead become constipated. Apply like single treatment session, drinking one small pot of tea 3 days in a row, then you're done. Repeat after 1-2 months if needed. This is relevant in reference to the discussion on various illnesses being caused by parasites: there's no need to by horse de-wormer or any other substance, you can pick nettle leaves yourself and make tea. Pick some extra, let them try on a plate and save some in a container and they last all year.