Mental Prayer
"If you are speaking to someone you really love,
you don't say 'Wait a minute', and pull out a book and read to them.
No, you speak from your heart."
-Ady Castañeda
What is mental prayer? It is speaking to God from your heart, with your own words. This is not to say that the beautfully worded written prayers of the Church are inferior. But they can't be our only form of communication with God. We need to use those prayers as a springboard, to launch us into spontaneous conversation, heartfelt, unique to us and our experience with God.

Meditation engages thought, imagination, emotion, and desire. This mobilization of faculties is necessary in order to deepen our convictions of faith, prompt the conversion of our heart, and strengthen our will to follow Christ. Christian prayer tries above all to meditate on the mysteries of Christ, as in lectio divina or the rosary. This form of prayerful reflection is of great value, but Christian prayer should go further: to the knowledge of the love of the Lord Jesus, to union with him.
Catechism of the Catholic Church #2708