Here are some prayers of preparation for Mass, from Appendix I of the Sacramentary (pp. 1010-1014).
Prayer of St. Thomas Aquinas
Lord, Father all-powerful and ever-living God,
I thank you,
for even though I am a sinner, your unprofitable servant,
not because of my worth but in the kindness of your mercy,
you have fed me
with the precious body and blood of your Son, our Lord Jesus Christ.
I pray that this communion
may not bring me condemnation and punishment
but forgiveness and salvation.
May it be a helmet of faith
and a shield of good will.
May it purify me from evil ways
and put an end to my evil passions.
May it bring me charity and patience,
humility and obedience,
and growth in the power to do good.
May it be my strong defense
against all my enemies, visible and invisible,
and the perfect calming of all my evil impulses,
bodily and spiritual.
May it unite me more closely to you,
the one true God,
and lead me safely through death
to everlasting happiness with you.
And I pray that you will lead me, a sinner,
to the banquet where you,
with your Son and Holy Spirit,
are true and perfect light,
gladness without end,
and perfect happiness to your saints.
Grant this through Christ our Lord. Amen.
Prayer to our Redeemer (Anima Christi)
Soul of Christ, make me holy.
Body of Christ, be my salvation.
Blood of Christ, let me drink your wine.
Water flowing from the side of Christ, wash me clean.
Passion of Christ, strengthen me.
Kind Jesus, hear my prayer;
hide me within your wounds and keep me close to you.
Defend me from the evil enemy.
Call me at my death
to the fellowship of your saints,
that I may sing your praise with them
through all eternity. Amen.
Prayer of Self-Dedication to Jesus Christ
Lord Jesus Christ,
take all my freedom,
my memory, my understanding, and my will.
All that I have and cherish
you have given me.
I surrender it all to be guided by your will.
Your grace and your love
are wealth enough for me.
Give me these, Lord Jesus,
and I ask for nothing more.
Prayer to Jesus Christ Crucified
My good and dear Jesus,
I kneel before you,
asking you most earnestly
to engrave upon my heart
a deep and lively faith, hope and charity,
with true repentance for my sins,
and a firm resolve to make amends.
As I reflect upon your five wounds,
and dwell upon them with deep compassion and grief,
I recall, good Jesus, the words the prophet David spoke
long ago concerning yourself:
they have pierced my hands and feet,
they have counted all my bones.
The Universal Prayer (Attributed to Pope Clement XI)
Lord, I believe in you: increase my faith.
I trust in you: strengthen my trust.
I love you: let me love you more and more.
I am sorry for my sins: deepen my sorrow.
I worship you as my first beginning,
I long for you as my last end,
I praise you as my constant helper,
and call on you as my loving protector.
Guide me by your wisdom,
correct me with your justice,
comfort me with your mercy,
protect me with your power.
I offer you, Lord, my thoughts: to be fixed on you;
my words: to have you for their theme;
my actions: to reflect my love for you;
my sufferings: to be endured for your greater glory.
I want to do what you ask of me:
in the way you ask,
for as long as you ask,
because you ask it.
Lord, enlighten my understanding,
strengthen my will,
purify my heart,
and make me holy.
Help me to repent of my past sins
and to resist temptation in the future.
Help me to rise above my human weaknesses
and to grow stronger as a Christian.
Let me love you, my Lord and my God,
and see myself as I really am:
a pilgrim in this world,
a Christian called to respect and love
all whose lives I touch,
those in authority over me
or those under my authority,
my friends and my enemies.
Help me to conquer anger with gentleness,
greed by generosity,
apathy by fervor.
Help me to forget myself
and reach out toward others.
Make me prudent in planning,
courageous in taking risks.
Make me patient in suffering, unassuming in prosperity.
Keep me, Lord, attentive at prayer,
temperate in food and drink,
diligent in my work,
Let my conscience be clear,
my conduct without fault,
my speech blameless,
my life well-ordered.
Put me on guard against my human weaknesses.
Let me cherish your love for me,
keep your law,
and come at last to your salvation.
Teach me to realize that this world is passing,
that my true future is the happiness of heaven,
that life on earth is short,
and the life to come eternal.
Help me to prepare for death,
with a proper fear of judgment,
but a greater trust in your goodness.
Lead me safely through death
to the endless joy of heaven.
Grant this through Christ our Lord. Amen.
Prayer to the Virgin Mary
Mary, holy virgin mother,
I have received your Son, Jesus Christ.
With love you became his mother,
gave birth to him, nursed him,
and helped him grow to manhood.
With love I return him to you,
to hold once more,
to love with all your heart,
and to offer to the Holy Trinity
as our supreme act of worship
for your honor and for the good
of all your pilgrim brothers and sisters.
Mother, ask God to forgive my sins
and to help me serve him more faithfully.
Keep me true to Christ until death,
and let me come to praise him with you
for ever and ever. Amen.