Prayer 

"Prayer is the raising of one's mind and heart to God or the requesting of good things from God."2 But when we pray, do we speak from the height of our pride and will, or "out of the depths" of a humble and contrite heart?3 He who humbles himself will be exalted;4 humility is the foundation of prayer, Only when we humbly acknowledge that "we do not know how to pray as we ought,"5 are we ready to receive freely the gift of prayer. "Man is a beggar before God." (CCC 2559)
The Section of Prayer from the Catechism of the Catholic Church

Fasting 

It is a traditional doctrine of Christian spirituality that a constituent part of repentance, of turning away from sin and back to God, includes some form of penance, without which the Christian is unlikely to remain on the narrow path and be saved (Jer 18:11, 25:5; Ez  18:30, 33:11-15; Joel 2:12; Mt 3:2; Mt 4:17; Acts 2:38). Christ Himself said that His disciples would fast once He had departed (Lk 5:35). The general law of penance, therefore, is part of the law of God for man.
​Mother Adela, SCTJM, Foundress
​ talk on Fasting

Almsgiving

The foundational call of Christians to charity is a frequent theme of the Gospels.  During Lent, we are asked to focus more intently on "almsgiving," which means donating money or goods to the poor and performing other acts of charity.  As one of the three pillars of Lenten practice, almsgiving is "a witness to fraternal charity" and  "a work of justice pleasing to God." (Catechism of the Catholic Church, no. 2462). 
New Advent Article on Almsgiving