Never forget the Holy Souls in Purgatory they cannot pray for themselves but they can pray for you!
I pray every day for the Holy Souls, their greatest suffering is to be deprived of the beatific vision of God.
They will never forget you and will always be grateful to you for shortening their time in Purgatory. The most powerful way to do this is to offer mass for the Holy Souls [or even get a special mass said for them]
This is a prayer given by Our Lord to St.Gertrude the Great which will release many souls from Purgatory each time it is said:
PRAYER OF ST GERTRUDE THE GREAT
ETERNAL FATHER I OFFER YOU THE MOST PRECIOUS BLOOD OF YOUR DIVINE SON JESUS, IN UNION WITH THE MASSES SAID THROUGHOUT THE WORLD TODAY, FOR ALL THE HOLY SOULS IN PURGATORY, FOR SINNERS EVERYWHERE, FOR SINNERS IN THE UNIVERSAL CHURCH, THOSE IN MY OWN HOME AND WITHIN MY FAMILY
AMEN
Everybody has someone in Purgatory just waiting for a prayer to be released, remember the Holy Souls will repay you a hundredfold!