“Let him be instant in continual ardour, dismissing all but his sheer needs to eat and sleep. For know that the true Formula whose virtue sufficed the Beast in this Attainment, was thus: INVOKE OFTEN. So may all men come at last to the Knowledge and Conversation of the Holy Guardian Angel: thus sayeth the Beast.”
– Aleister Crowley, “Liber Samekh“

“The secret of success in invocation has not hitherto been disclosed. It is an exceedingly simple one. It is practically of no importance whatever that the invocation should be ‘right.’ There are a thousand different ways of compassing the end proposed, so far as external things are concerned. The whole secret may be summarised in these four words: ‘Enflame thyself in praying.'”
-Aleister Crowley, Magick in Theory & Practice, chapter 15

“Neglect never the fourfold Adoration of the Sun in his four Stations, for thereby thou dost affirm thy Place in Nature and her Harmonies. [Liber Resh]

Neglect not the Performance of the Ritual of the Pentagram, and of the Assumption of the Form of Hoor-pa-Kraat. [Liber O, part III]

Neglect not the daily Miracle of the Mass, either by the Rite of the Gnostic Catholic Church [Liber XV], or that of the Phoenix [Mass of the Phoenix].

Neglect not the Performance of the Mass of the Holy Ghost [9th degree OTO practice], as Nature Herself prompteth thee.

Travel much also in the Empyrean in thy Body of Light, seeking ever Abodes more fiery and lucid. [Liber O, parts V-VI]

Finally, exercise the Eight Limbs of Yoga. [Liber E]”
– Aleister Crowley, Liber Aleph, references added