There is no progress in prayer without progress in faith, a purification of faith. And this entails the removal of all the props which depend on human endeavor, human reasoning, signs and the rest. It is the naked faith which is a terrifying experience and yet is the meeting point ultimately between God and ourselves in the depth of our being. This experience of the purification of faith is not normally one which comes early in the spiritual life. We must learn to wait.
In prayer, I am learning to observe the silences between the words. I am learning that I don't have to fill the empty space because the space will eventually sing for itself. The waiting and listening and silence teach that the active work of prayer must be balanced by the humble acceptance of grace.