When Martin Luther’s barber (and friend) asked him how to pray, Martin Luther responded with a brief treatise published in the spring of 1535 under the title A Simple Way to Pray, for a Good Friend. Luther explained his own practices of prayer.

The following are some of the suggestions Luther gave to his barber:

1. There is need for concentration
   Let prayer be the first business of the morning and last in the evening. Do not be sidetracked. Luther writes, “So, a good and attentive barber keeps his thoughts, attention, and eyes on the razor and hair and does not forget how far he has gotten with his shaving or cutting. If he wants to engage into much conversation or let his mind wander or look somewhere else he is likely to cut his customer’s mouth, nose, or even his throat. Thus if anything is to be done well, it requires the full attention of all one's senses and members. . .” (p. 32-33).
    
2. There is a sequence of prayer
   Luther writes ". . .kneel or stand with your hands folded and your eyes toward heaven and speak or think as briefly as you can. . .” (p.20). Offer a brief prayer “O Heavenly Father, dear God, I am a poor unworthy sinner, I do not deserve to raise my eyes or hands toward thee or to pray. . .” (p. 21) Begin to pray one petition of the Lord’s Prayer or one of the Ten Commandments. Never doubt you are alone in your prayer. “Do not leave your prayer without having said or thought, ‘Very well, God has heard my prayer, this I know as a certainty and a truth.’ This is what Amen means” (p. 29).
    
3. The heart must be ready for prayer
   Keep prayers meaningful. Unclutter your mind by focusing on one thought, perhaps one petition of the Lord’s Prayer or one of the Ten Commandments.
    
4. Prayer is like a garland of four twisted strands
   This garland is especially true when using Holy Scripture, Lord’s Prayer, or Ten Commandments. Each strand can be posed as a question:
   What is the (petition, commandment, etc) teaching/meaning for me?
   What prayer of thanksgiving does this prompt?
   What confession or lament does it evoke?
   What is the prayer petition?

Luther said, “Nothing can be said here about the part of faith and Holy Scriptures [in prayer] because there would be no end to what could be said. With practice one can take the Ten Commandments on one day, a psalm or chapter of Holy Scripture the next day, and use them as flint and steel to kindle a flame in the heart” (p.56).

--Quotes are from Martin Luther, A Simple Way to Pray, Louisville, Kentucky: Westminster Knox Press, 2000.