In order to pray with fruit and without distraction it is most useful and almost necessary to spend some time in meditation or pious reflection on some supernatural truth . . . As soon as you feel an impulse to pray while meditating, give way to it at once in the best way you can, by devout acts and petitions; in other words, begin your conversation with God on the subject about which you have been thinking.
-- Adapted from the leaflet Is Mental Prayer Easy?