John Calvin's third rule of prayer was that we must always pray with genuine feeling. Prayer is a matter of passion: "Many repeat prayers in a perfunctory manner from a set form, as if they were performing a task to God ... They perform the duty from custom, because their minds are meanwhile cold, and they ponder not what they ask."
A fourth rule of prayer from Calvin was that it be always accompanied by repentance: "God does not listen to the wicked; that their prayers, as well as their sacrifices, are an abomination to them. For it is right that those who seal up their hearts should find the ears of God closed against them."
Calvin said a humble submission is required: "Of this submission, which casts down all haughtiness, we have numerous examples in the servants of God. The holier they are, the more humbly they prostrate themselves when they come into the presence of the Lord."
If I can summarize Calvin's teaching on prayer succinctly, I would say this: The chief rule of prayer is to remember who God is and to remember who you are. If we remember those two things, our prayers will always and ever be marked by adoration and confession.
Do you pray with genuine feeling? Do you always accompany your prayers with repentance?