God cares for us as children. God will see us through our lives. But the things for which we pray may not be what God intends for us. The reason we pray publicly is to hold each other to high standards of Christian conduct, to challenge each other to respond in Christ's name to those in need, to remind each other that we are not alone in this pilgrimage through life. When we pray for the sick, for example, we remind each other that we bear each other's burdens, that we share a faith that God will work for good through us and through those for whom we pray, that those for whom we pray are part of us, though absent from us.
Prayer bears no relation to magic.
Prayer relieves anxiety. Prayer reminds us of our relative helplessness in life. There is just so much we can do by dint of our own effort. Because we surrender our wills in prayer, prayer frees. There is no secret, then, to prayer.