"The function of prayer is not to influence God, but rather to change the nature of the one who prays."
The tradition of the Catholic Church highlights four basic elements of Christian prayer: (1) Prayer of Adoration/Blessing, (2) Prayer of Contrition/Repentance, (3) Prayer of Thanksgiving/Gratitude, and (4) Prayer of Supplication/Petition/Intercession. These elements may be easily remembered using the acronym ACTS: Adoration, Contrition, Thanksgiving, Supplication.
"Rejoice evermore. Pray without ceasing. In every thing give thanks: for this is the will of God in Christ Jesus concerning you."
1 Thessalonians 5:16-18
"Call unto me, and I will answer thee, and show thee great and mighty things, which thou knowest not."
Jeremiah 33:3
"In my distress I called upon the Lord, and cried unto my God: he heard my voice out of his temple, and my cry came before him, even into his ears."
Psalm 18:16
"Ye have not chosen me, but I have chosen you, and ordained you, that ye should go and bring forth fruit, and that your fruit should remain: that whatsoever ye shall ask of the Father in my name, he may give it you."
John 15:16
"The Lord is nigh unto all them that call upon him, to all that call upon him in truth."
Psalm 145:18