It takes practice to spot angelic presences. But practice alone is not enough, unless one can practice being taken by surprise.
If we are designed to be in communion with God, if God is our Lover, then we have to indulge in the things that lovers do. The lover wishes always to be in the loved one's presence, to gaze and behold. The name for this loving regard is contemplation.
Prayer begins in us the restoration of the divine image, in all its hiddenness and wonder. It brings us closer to the "region of likeness" and every prayer is an act of letting the old self go. It involves "dying". The grain of wheat falls into the ground and dies. Dead, it is destined to bear much fruit.