I think we've all learned "Thank-You" prayers. But Rejoicing is a bit more than saying thank-you. Rejoicing is the lingering happiness of victory. Rejoicing is triumphant.
Jesus makes us joyful. Joy is at the very heart of the Christian experience. Christmas, Easter, Pentecost -- joyful celebrations, all. Prayer should always include joy. Even the most solemn of prayers should be rooted in the triumphant joy of Christ's Easter victory.
Practice rejoicing. It's good for your soul and sweet music in God's ears.