I forget whether you’ve read my Advice to the Serious Seeker. If not, no matter. I mention it simply because what little I know on the subject of prayer, and feel confident enough about to discuss in a public forum like this, can be found in the fourth part of that book.
Many other books are available too, and it’s clear from your list of explorations that you’ve already read rather widely. But in the final analysis a book can’t teach you. You need the guidance of another, flesh-and-blood human being. And no legitimate guide will be able to help you until and unless you establish a sacramental relationship with a genuine, orthodox tradition. Prayer presupposes sincerity, and sincerity demands faith and commitment.
In the meantime, of course, you can always offer up personal prayers—spontaneous requests for God’s help, woven of humility and trust. These last words are crucial. He who wishes to pray must be prepared to put himself, his agenda, his expectations aside. You speak of having investigated many methods and techniques. But the technique—if you will allow me to speak like the Zen masters—consists in realizing there is no technique.
There is instead a crystal-clear space opened up by our resignation and attentive listening.