A Catholic checklist for the changing year

1. Go to Sunday Mass (Feast of the Holy Family)

It's a mortal sin if you don't unless a serious reason (Catechism).

2. Consecrate your family to the Holy Family

"Jesus, Mary, Joseph, Anne, Joachim, we consecrate our hearts and our descent to your hearts."

(or use your favorite consecration or own words, remembering that consecrating to the heart is better than just to the Saint's name).

3. Thanksgiving

Pray the Te Deum (on Dec 31st evening, Theotokos vigil)

O God, we praise Thee, and acknowledge Thee to be the supreme Lord. 
Everlasting Father, all the earth worships Thee. 
All the Angels, the heavens and all angelic powers, 
All the Cherubim and Seraphim, continuously cry to Thee: 
Holy, Holy, Holy, Lord God of Hosts! 
Heaven and earth are full of the Majesty of Thy glory. 
The glorious choir of the Apostles, 
The wonderful company of Prophets, 
The white-robed army of Martyrs, praise Thee. 
Holy Church throughout the world acknowledges Thee: 
The Father of infinite Majesty; 
Thy adorable, true and only Son; 
Also the Holy Spirit, the Comforter. 
O Christ, Thou art the King of glory! 
Thou art the everlasting Son of the Father. 
When Thou tookest it upon Thyself to deliver man, 
Thou didst not disdain the Virgin's womb. 
Having overcome the sting of death, Thou opened the Kingdom of Heaven to all 
believers. 
Thou sitest at the right hand of God in the glory of the Father. 
We believe that Thou willst come to be our Judge. 
We, therefore, beg Thee to help Thy servants whom Thou hast redeemed with Thy 
Precious Blood. 
Let them be numbered with Thy Saints in everlasting glory.

V. Save Thy people, O Lord, and bless Thy inheritance! 
R. Govern them, and raise them up forever.

V. Every day we thank Thee. 
R. And we praise Thy Name forever, yes, forever and ever.

V. O Lord, deign to keep us from sin this day. 
R. Have mercy on us, O Lord, have mercy on us.

V. Let Thy mercy, O Lord, be upon us, for we have hoped in Thee. 
R. O Lord, in Thee I have put my trust; let me never be put to shame.

Amen

Or in Latin:

Te Deum laudamus: te Dominum confitemur. 
Te aeternum Patrem omnis terra veneratur. 
Tibi omnes Angeli; tibi caeli et universae Potestates; 
Tibi Cherubim et Seraphim incessabili voce proclamant: 
Sanctus, Sanctus, Sanctus, Dominus Deus Sabaoth. 
Pleni sunt caeli et terra maiestatis gloriae tuae. 
Te gloriosus Apostolorum chorus, 
Te Prophetarum laudabilis numerus, 
Te Martyrum candidatus laudat exercitus. 
Te per orbem terrarum sancta confitetur Ecclesia, 
Patrem immensae maiestatis: 
Venerandum tuum verum et unicum Filium; 
Sanctum quoque Paraclitum Spiritum. 
Tu Rex gloriae, Christe. 
Tu Patris sempiternus es Filius. 
Tu ad liberandum suscepturus hominem, non horruisti Virginis uterum. 
Tu, devicto mortis aculeo, aperuisti credentibus regna caelorum. 
Tu ad dexteram Dei sedes, in gloria Patris. 
Iudex crederis esse venturus. 
Te ergo quaesumus, tuis famulis subveni: quos pretioso sanguine redemisti. 
Aeterna fac cum sanctis tuis in gloria numerari.

V. Salvum fac populum tuum, Domine, et benedic hereditati tuae. 
R. Et rege eos, et extolle illos usque in aeternum.

V. Per singulos dies benedicimus te. 
R. Et laudamus nomen tuum in saeculum, et in saeculum saeculi.

V. Dignare, Domine, die isto sine peccato nos custodire. 
R. Miserere nostri, Domine, miserere nostri.

V. Fiat misericordia tua, Domine, super nos, quemadmodum speravimus in te. 
R. In te, Domine, speravi: non confundar in aeternum.

Amen

Note: Te Deum, also sometimes called the Ambrosian Hymn because of its association with St. Ambrose, is a traditional hymn of joy and thanksgiving. First attributed to Sts. Ambrose, Augustine, or Hilary, it is now accredited to Nicetas, Bishop of Remesiana; (4th century). 
It is used at the conclusion of the Office of the Readings for the Liturgy of the Hours on Sundays outside Lent, daily during the Octaves of Christmas and Easter, and on Solemnities and Feast Days. 
The petitions at the end were added at a later time and are optional. 
A partial indulgence is granted to the faithful who recite it in thanksgiving and a plenary indulgence is granted if the hymn is recited publicly (like the family gathering) on the last day of the year, with the general conditions:

The following "General remarks on Indulgences" from Gift of the Indulgence summarizes the usual conditions given in the Church's law (cf. Apostolic Penitentiary, Prot. N. 39/05/I):

This is how an indulgence is defined in the Code of Canon Law (can. 992) and in the Catechism of the Catholic Church (n. 1471): "An indulgence is a remission before God of the temporal punishment due to sins whose guilt has already been forgiven, which the faithful Christian who is duly disposed gains under certain prescribed conditions through the action of the Church which, as the minister of redemption, dispenses and applies with authority the treasury of the satisfactions of Christ and the saints".
In general, the gaining of indulgences requires certain prescribed conditions (below, nn. 3, 4), and the performance of certain prescribed works .....

To gain indulgences, whether plenary or partial, it is necessary that the faithful be in the state of grace at least at the time the indulgenced work is completed.  [i.e. one must be a Catholic, not excommunicated or in schism.]

A plenary indulgence can be gained only once a day. In order to obtain it, the faithful must, in addition to being in the state of grace: 

1. have the interior disposition of complete detachment from sin, even venial sin;
2. have sacramentally confessed their sins;
3. receive the Holy Eucharist (it is certainly better to receive it while participating in Holy Mass, but for the indulgence only Holy Communion is required);
4. pray for the intentions of the Supreme Pontiff.

It is appropriate, but not necessary, that the sacramental Confession and especially Holy Communion and the prayer for the Pope's intentions take place on the same day that the indulgenced work is performed; but it is sufficient that these sacred rites and prayers be carried out within several days (about 20) before or after the indulgenced act. Prayer for the Pope's intentions is left to the choice of the faithful, but an "Our Father" and a "Hail Mary" are suggested. One sacramental Confession suffices for several plenary indulgences, but a separate Holy Communion and a separate prayer for the Holy Father's intentions are required for each plenary indulgence.
For the sake of those legitimately impeded, confessors can commute both the work prescribed and the conditions required (except, obviously, detachment from even venial sin).
Indulgences can always be applied either to oneself or to the souls of the deceased, but they cannot be applied to other persons living on earth.

https://www.ewtn.com/catholicism/devotions/te-deum-381

https://www.ewtn.com/catholicism/devotions/conditions-13362

4. Veni, Creator Spiritus (Come Holy Spirit, Creator Blest)

Plenary indulgence with the general conditions if prayed on January 1st (Theotokos feast)

One of the most widely used hymns in the Church, Veni, Creator Spiritus, is attributed to Rabanus Maurus; (776-856). It is used at Vespers, Pentecost, Dedication of a Church, Confirmation, and Holy Orders and whenever the Holy Spirit is solemnly invoked. A partial indulgence is granted to the faithful who recite it. A plenary indulgence is granted if it is recited on January 1st or on the feast of Pentecost.

Come, Holy Spirit, Creator blest, and in our souls take up Thy rest; come with Thy grace and heavenly aid to fill the hearts which Thou hast made.

O comforter, to Thee we cry, O heavenly gift of God Most High, O fount of life and fire of love, and sweet anointing from above.

Thou in Thy sevenfold gifts are known; Thou, finger of God's hand we own; Thou, promise of the Father, Thou Who dost the tongue with power imbue.

Kindle our sense from above, and make our hearts o'erflow with love; with patience firm and virtue high the weakness of our flesh supply.

Far from us drive the foe we dread, and grant us Thy peace instead; so shall we not, with Thee for guide, turn from the path of life aside.

Oh, may Thy grace on us bestow the Father and the Son to know; and Thee, through endless times confessed, of both the eternal Spirit blest.

Now to the Father and the Son, Who rose from death, be glory given, with Thou, O Holy Comforter, henceforth by all in earth and heaven.

Amen.

In Latin:

Veni, Creator Spiritus, mentes tuorum visita, imple superna gratia quae tu creasti pectora.

Qui diceris Paraclitus, altissima donum Dei, fons vivus, ignis, caritas, et spiritalis unctio.

Tu, septiformis munere, digitus paternae dexterae, Tu rite promissum Patris, sermone ditans guttura.

Accende lumen sensibus: infunde amorem cordibus: infirma nostri corporis virtute firmans perpeti.

Hostem repellas longius, pacemque dones protinus: ductore sic te praevio vitemus omne noxium.

Per te sciamus da Patrem, noscamus atque Filium; Teque utrisque Spiritum credamus omni tempore.

Deo Patri sit gloria, et Filio, qui a mortuis surrexit, ac Paraclito, in saeculorum saecula.

Amen.

5. Get a Patron Saint for the new year

Saint Faustina's diary (The Divine Mercy in my soul), 360:

When we came to the refectory for breakfast, after we had said our goodbyes, the drawing of the patrons began. When I approached the pictures on which the patron saints are written, I took them without thinking, but without reading immediately; I wanted to mortify myself for a few minutes. Then I hear a voice in my soul: I am your patron, read. At that moment I looked at the inscription and read: patron saint for 1935 – the Blessed Eucharist. My heart trembled with joy.

Write the names of Jesus, Mary, Joseph, Anne, Joachim and all the Saints you know in peaces of paper and mix them.

After praying for God's will to be done in choosing the personal Patron Saint for the new year (and a Hail Mary if you wish), each picks up one randomly.

"Consider it the Lord’s hand leading you to that particular Saint. Read about his life and make friends with your patron. Tell him or her your thoughts and fears. Ask for their intercession in your life. Ask that you might acquire the virtues your patron excelled in. They will hear your prayers and help you overcome all the trials you’ll face this New Year."

Remember to pray to your patron along the year and to thank for all the graces received!

6. Go to Theotokos Mass (Mary Mother of God)

It's a mortal sin if you don't unless a serious reason (Catechism).

7. To Do list

your main item is to become a Saint and the means to it.

That's the purpose of your life: to know, love and serve God!

Reminder: avoid common New Year's party sins

• Superstitions
• Don't eat or drink too much (drunkedness is a mortal sin)
• Lust (sex outside marriage is a mortal sin, even sexual delectation not directed to your spouse like glances, phantasies or desire)

Remember to greet:

Merry Christmas (until Jan 7), happy Holy Family, Theotokos and 2024!