In a hundred ways. We do it with our words, as well as with our prayerful and attentive listening. The greatest of all liturgical prayer is the Mass. But for many centuries before Vatican II, laity were unable to fully participate in this liturgical prayer. They could not feel part of a prayer that was spoken in a foreign language, where ritual gestures were hidden because the priest had his back to them, where songs are sung by the choir, and where they were silent observers.
Liturgical prayer contains many elements.
Our participation by praying aloud and singing is liturgical prayer. When we dip our hand into the water at the font, a reminder of our baptism in Christ, when we sit in silence, listening to the Word of God, when we walk in procession to receive the Body of Christ in communion, when we lift our hands humbly to receive the Bread of Life and say, 'Amen,' we are praying liturgically. When we serve as a lector, eucharistic minister, choir member or minister of hospitality, we are praying liturgically. Even a simple gesture of standing, bowing, genuflecting is a liturgical prayer. Music too becomes prayer.