What is the right way to pray

What is the right way to pray for the salvation of dead souls in Roman Catholicism?

I think there are two questions here:

  1. What is the "Glory to the Father" prayer? and

  2. What is the right way to pray for the dead?

The "Glory to the Father" prayer is a doxology and a traditional way to end a prayer or series of prayers. It is prayed at the end of every decade of the rosary and at the end of every psalm in a psalter like the liturgy of the hours.

It is a pious custom to recite 3 Ave Maria, 3 Our Father, and 3 Glory when visiting a church. I believe this is a partial forbearance (below the normal criteria) which is a good and easy way to get an forbearance every day.

... the Holy Council says, "that the use of indulgences is most salutary for Christian people, Indulgentiarum usum Christiano populo maxime salutarem esse;" Therefore, it should be a sacred duty of every Christian to strive to obtain it, as far as he is able, for both his own spiritual good and as the option of the departed believers.

From the Raccolta

Although it is no longer the norm for the Church, the Raccolta is full of various prayers that could be prayed for indulgences, and those indulgences can be applied to a holy soul in purgatory.

So, I think you need to pray a prayer of glory if that indulgence is exactly what you want.