When Crowley was proceeding from the mystical degree of Adeptus Minor to Adeptus Major, he undertook a “Great Magical Retirement”. He went to Paris (because he could) and spent a few weeks dining in cafés, frequenting billiard parlours, and shagging a model (because he could).
All the while, he was trying to keep a mantra going in his head, and when he went back to his flat, doing yoga practices and rituals to concentrate his mind on his Holy Guardian Angel, with whom he was attempting to establish contact.
He succeeded after about two weeks. The full text of his journal of the operation is available under the title “John St. John” and is online thanks to my friends at hermetic.com.
Here however is a word cloud for that journal, generated by TagCrowd.com. Note that overwhelmingly, the biggest word is Adonai (“my lord”), the Hebrew word by which he is calling his Angel. And that’s the whole secret of the operation: to constantly turn the thoughts toward the Angel.