To him therefore who knoweth to do good, and doth it not, to him it is sin (James 4:17)
There are a variety of ways to help the Holy Souls. Some of which are listed in a previous post, others are below. Keep in mind virtually everthing and anything can be offered to God as an act of love and charity for them. "Lord, may each movement of my hand today be for your glory and for the assistance of your faithful departed. Amen+" Practiced regularly, you will be shocked at what your little prayers and offerings have merited you at your particular judgement!
"The Holy Sacrifice is the greatest help we can offer, because its effect depends on itself, and not on the piety of the priest who offers it...If we cannot have a Mass said, we should at least hear Mass for our dear departed. A Mass has infinite merit..." (My Catholic Faith; 1949-1954)
In addition to the Requiem Mass following death, a Mass for the departed may be arranged for just about any day of the year. The following are days of traditional significance for Masses for the Departed:
1. All Souls Day
2. Third day/year following burial (Christ's time in the tomb); Seventh day/year (symbolic of eternal repose; St. Ambrose) and 30th day/year (St. Ambrose) from death or burial.
3. Yearly anniversary day from death or burial
4. Gregorian Masses: 30 consecutive Masses following the repose (burial) popularized by 6th Century Pope St. Gregory the Great. This could also be ANY 30 days following the death of a person because God hears all prayers outside of time.
5. Purgatorian Society Masses: daily masses said for souls those enrolled.