When going to church, it is best to pray mentally, for example, read the 50th and 90th Psalms, the Jesus Prayer.
I rejoiced at those who said to me: Let us go to the house of the Lord. And through the multitude of Thy mercy, O Lord, I will go into Thy house, I will bow down to Thy holy temple, in Thy fear. Lord, guide me in Your righteousness, for my sake, my enemy, straighten my path before You, so that without stumbling I will glorify the One Divinity, the Father, and the Son, and the Holy Spirit, now and forever, and to the ages of ages. Amen.
I will go into Your house, I will bow to Your holy temple in Your passion. Lord, guide me in Your righteousness, for my sake, my enemy, straighten my path before You. For there is no truth in their mouths, their hearts are in vain, their tombs are opened, their tongues are flatterers. Judge them, O God, that they may fall away from their thoughts: according to the multitude of their wickedness, I despise them, for I have grieved Thee, O Lord.
And let all who trust in You rejoice, may they rejoice forever, and dwell in them, and let those who love Your Name boast in You. For you have blessed the righteous, O Lord, for you have crowned us with weapons of favor.
(This prayer is read by the clergy when they enter the altar. It is good for every believer to read this prayer before entering the temple).
1 Orthodox prayer book with an appendix of prayers to the Most Holy Theotokos and the holy saints of God. - M.: Publishing house of the Moscow Patriarchate of the Russian Orthodox Church, 2018. - 816 p.
2 Practical liturgical guidance for clergy.