This topic covers the next three sections of the document HCWEOM. Most of it is nothing new for Catholics. But you never know when an important point will pop out for you. Let’s read:
23. The Eucharist, which continuously makes the paschal mystery of Christ to be present among us, is the source of every grace and of the forgiveness of sins. Nevertheless, those who intend to receive the body of the Lord must approach it with a pure conscience and proper dispositions of soul if they are to receive the effects of the paschal sacrament.
On this account the Church prescribes “that those conscious of mortal sin, even though they think themselves to be contrite, must not go to the Holy Eucharist without sacramental confession beforehand.” (See Council of Trent, sess.13, Decr. De Eucharistia 7: Denz-Schon 1646-1647; sess. 14, Canones de sacramento Paentitentiae 9: Denz-Schon 1709. SCDF, Pastoral Norms on Giving General Sacramental Absolution, June 16, 1972, Preface and Norm VI [DOL 361, nos. 3038 and 3044].
When there is a serious reason and no opportunity for confession, they are to make an act of perfect contrition with the intention of confessing individually, as soon as possible, the mortal sins that they cannot confess at present.
It is desirable that those who receive Communion daily or very often go to the sacrament of penance at regular intervals, depending on their circumstances.
The faithful also should look upon the Eucharist as a remedy that frees them from their daily faults and preserves them from mortal sins; they should also receive an explanation of how to make use of the penitential parts of the liturgy, especially at Mass. (Eucharisticum Mysterium 35)
The Communion fast:
24. Communicants are not to receive the sacrament unless they have fasted for at least one hour from food and beverages, with the exception only of water and medicine.
And a pragmatic exception:
The elderly and those suffering from any kind of infirmity, as well as those who take care of such persons, may receive the Eucharist even if they have taken something within the hour before Communion. (Canon Law 1917, 919.1 & 3)
Keep in mind the Eucharist is source and summit of the Christian life. This document devotes a whole section of what is to take place after the celebration to complement the two that detail what is to take place before:
25. The union with Christ, it which the sacrament is directed, should be extended to the whole of Christian life. Thus the faithful, constantly reflecting upon the gift they have received, should carry on their daily work with thanksgiving, under the guidance of the Holy Spirit, and should bring forth fruits of rich charity.
In order to continue more surely in the thanksgiving that in the Mass is offered to God in an eminent way, those who have been nourished by Communion should be encouraged to remain for some time in prayer. (Eucharisticum Mysterium 38)
The perfect balance for the Christian life: prayer and charity, contemplation and action, ora et labora.