A Christian should approach prayer not as a means to earn favor, but as an act of obedience and thankful reliance on God, grounded in the promises of the gospel. Reformed traditions emphasize that prayer is to be offered in the name of Christ, by the help of the Holy Spirit, with a heart of humble confession and sincere desire.
Prayer is not an optional exercise for the spiritual elite; it is a solemn duty commanded by God. As noted in the Large Catechism Introduction §5, calling upon the name of the Lord is as much a command as the Ten Commandments. However, the gospel transforms this duty from a burden into a privilege. We do not approach God because we are holy, but because He has invited us to draw near despite our sin. As taught in the Large Catechism Introduction §10, our hearts often flee from God because we feel unworthy, yet we must remember that God does not base the efficacy of our prayers on our own merit, but on His command and His promise to hear us. Prayer is to be made in the name of Christ, by the help of His Spirit, and according to His will (Westminster Confession of Faith Ch.21 §3).
Because we are naturally dull and prone to wander, Christ Himself has taught us how to pray. The Lord's Prayer serves as our special rule and guide. True prayer is the offering up of our desires to God for things agreeable to His will (Westminster Shorter Catechism Q.98). It is a dialogue of trust, fueled by the assurance that God is a loving Father who delights to give to His children. This is confirmed in Matthew 7:7, which says, 'Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you.' When we pray, we confess our deep need and acknowledge His mercy, resting in the work of Christ rather than our own efforts.