Your Father Loves You by James Packer, Harold Shaw Publishers, 1986, page for June 3
Each Christian's prayer life, like every good marriage, has in it common factors about which one can generalize and also uniquenesses which no other Christian's prayer life will quite match. You are you, and I am I, and we must each find our own way to God; and there is no recipe for prayer that can work for us like a handyman's do-it-yourself manual or a cookery book, where the claim is that if you follow the instructions you can't go wrong.
Praying is not like carpentry or cookery; it is the active exercise of a personal relationship: a kind of friendship with the living God and his Son Jesus Christ, and the way it goes is more under divine control than under ours. Books on praying, like marriage manuals, are not to be treated with slavish superstition, as if the perfection of technique is the answer to all difficulties; their purpose, rather, is to suggest things to try. But as in other close relationships, in prayer you have to find out by trial and error what is right for you, and you learn to pray by praying.
Some of us talk more, others less; some are constantly vocal, others cultivate silence before God as their way of adoration; some slip into glossolalia, others make a point of not slipping into it; yet we may all be praying as God means us to do. The only rule is: Stay within the biblical guidelines, and within those guidelines, as John Chapman put it, "Pray as you can, and don't try to pray as you can't."