Normal meditation-forms help to concentrate on breathing and mental balance, and as man/woman gets his/her breathing more balanced, he can channel more energy easier. A simple meditation can play a role of just preparing for ritual. it is also good after the ritual if willed, for many rituals make initiate extremely creative compared to normal situation. Meditation after ritual is really recommended IMO, especially if you want to keep a close touch to art with your working.
Initiate should keep a close touch on the quality of meditation, for some meditations, when done wrong, are said to go closer in killing the mind, as normal meditationforms can be said (at least in Tibetian- Buddhish contect) to be about bringing the light of mind to surface, and to remove the veils of the mind.
Of course the preparation can be for example just sitting on chair and being quiet, as long as you slowly start preparing in what you are soon going to do. Everyone has their ways.
Especially if the ritual is complicated, containing many stages, and taking a lot of energy and concentration, it is conciderable to prepare really well.
I usually start preparing for rituals (especially in invocation/evocations) about 45 minutes before, and it usually contains also meditation, but not everytime. Starting a ritual is fucked up if you have all the thoughts about everything un-necessary in your head. But that is a simplicity.
Find your ways, try different technics. If you decide to use meditation, try to find a right way to do it.
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