Love is expressed in prayer, in conversation with Him. Prayer is the lifting of our minds to God. Other prayers, apart from the Holy Mass, are the Holy Rosary, Novenas, the Divine Mercy Chaplet, the Stations of the Cross and various invocations to Saints. When you pray without words, the soul may express devotion to Jesus, to the Blessed Virgin Mary or to Saints also. That would be mental prayer.
Meditation is a form of prayer too.