Mental prayer in my opinion is nothing else than an intimate sharing between friends; it means taking time frequently to be alone with Him who we know loves us. The important thing is not to think much but to love much and so do that which best stirs you to love. Love is not great delight but desire to please God in everything.
Remember that you are an actor in a drama of such sort as the Author chooses: if short, then in a short one; if long, then in a long one. If it be His pleasure that you should enact a poor man, or a cripple, or a ruler, or a private citizen, see that you act it well. For this is your business, to act well the given part. But to choose it belongs to Another.