Pope Shenouda III
Train yourself to pray the repetitive short prayers:
For example, the prayer: “My Lord Jesus Christ have mercy on me”, or “Make haste, O God, to deliver me! Make haste to help me,” or “I love the Lord Jesus Christ, and I bless His name”, or “I thank you Lord on every occasion”... or any short verse that you make up for yourself as a prayer and that suits your condition and expresses your feelings... By repeating a prayer, it makes it register in your subconscious so it will be in your thoughts automatically and may stay with you, even in your sleep. The saying of the Psalmist, “...I remember You on my bed” (Ps 63:6), refers to this.