Sean Oakes describes the spiritual qualities known as the five faculties or five powers that are especially helpful in meditation. In describing them, he lays out the way in which practicing each of the faculties in meditation encourages the development of the next faculty. He also provides a helpful description of the way in which mindfulness can help us to balance pairs of the faculties that can become problematic if either one of the pair becomes too strong. You can find his article here: The Five Faculties