The Church asks us to pray for our departed brothers and sisters. Remember them in your prayers today. One example of a prayer for the departed is:
Eternal rest grant unto them, O Lord, and let perpetual light shine upon them. May the souls of the faithful departed, through the mercy of God, rest in peace.
You could also offer up something today for the Souls in Purgatory, such as getting stuck in traffic, waking up early or having to pick up after someone else.