Henri Nouwen, in his journal from his months in a Trappist Monastery, The Genesee Diary, does quite a bit of reflecting on prayer - how it can be a struggle, how much it is needed, the ways in which it enhances our living.
However, in the end, perhaps it is simply something we need to do.
We like to explain things, but there is a sense in which prayer is beyond explanation. Equally, we like to understand things, but there is a sense in which prayer is to be experienced, rather than understood.
Nouwen writes this: "Writing about prayer is often very painful since it makes you so aware of how far away you are from the ideal you write about. .... While it is true that in order to pray you have to empty your heart and mind for God, you also have to empty your heart and mind of your feelings and ideas on prayer. Otherwise, prayer gets in the way of praying. .... It is hard not to desire good insights during prayer and not to fall into a long inner discussion with myself."
Of course, it is good to reflect about prayer sometimes - but the really important thing is to pray.