Zen and the art of archery. Your mind is at rest while your body is straining. Be the arrow. I read all the books years ago. What it finally came down to with me is using a deeper grip on my fingers. This is possible because I use a damascas glove.
I concentrate on hitting my anchor (middle finger in the corner of my mouth), getting that last little bit of pull with back tension, and then simply relaxing my fingers to release the string. On a good release my draw hand ends up with the tip of my index finger touching my right ear lobe.
When it all goes right I get perfect arrow flight and a good hit. When it goes wrong......well you know.
Good form, practice, and the consistency that comes with practice is the key.
I apologize if I have wandered off topic, but those are my thoughts (opinions).