It helps for children (and adults) to be able to mark and visibly follow the progress during Lent. An easy way to keep track is to make a Star Chart. Each person needs four categories or lines, and then 40 squares for each penitential day in Lent (Sundays aren't included) for each category.
Prayer and Spiritual Reading
Good Works and Almsgiving
Mortifications (or Sacrifices) and Self Denial
Penance (this is the area or areas of special practice or mortification that is done throughout Lent).
Teachers' stores have charts that could be easily adapted for this. Obtain stickers or stars in four different colors. At the end of the day, review the actions of the day, and place a star in each category that has been fulfilled that day.
A wonderful way to help younger children remind them to do penance during Lent, lima beans in a jar record each Lenten sacrifice.
It is hard to keep track of this treasure that is laid in Heaven if you are quite small and six weeks drag out like six years. We have made this part of the effort visible for the children so that they might see that they were accomplishing something. On or about Ash Wednesday, we dye lima beans purple to be used as counters in a jar. Beans, because they are seeds which, if put in the ground, appear to die only to spring forth with new life. This is what Our Lord said we must do if we would have life in Him. He that seems to lose his life shall gain it. The beans remind us that daily death to self in one self-denial after another is the dying which will find for us new life in Him.
Activity Source: Year and Our Children, The by Mary Reed Newland, P.J. Kenedy & Sons, New York, 1956