When it comes to prayer, believers are always on the lookout for the best way to commune with God and avoid practices that do not build up our relationship with Him. In all circumstances, we must know that our prayers are heard primarily because Jesus has made a way for us to the Father. That truth is the foundational basis upon which we pray.
Many times in scripture, Jesus condemned pharisees for praying aloud. In Luke 20:46-47, Jesus said, "Beware of the scribes, who like to walk around in long robes, and love greetings in the marketplaces and the best seats in the synagogues and the places of honor at feasts, who devour widows' houses and for a pretense make long prayers. They will receive the greater condemnation."
What Jesus really condemns here is a heart that is arrogant, not necessarily a prayer said in front of others. But there are other things we can get confused about when it comes to prayer and whether or not we're 'doing it right'.
Prayer is a matter of God's faithfulness not ours
What we must remember always is that it is through Jesus Christ that we now have access to God's presence and not our faithfulness. Hebrews 10:20 (NLT) tells us, "By his death, Jesus opened a new and life-giving way through the curtain into the Most Holy Place."
God does not base His answers on our faithfulness, but on His, and what is more, God does not favour the prayer of a zealous and excited Christian more than He does the prayer of a timid and humble one.
Pray with a humble heart
The most important thng that we can do when approaching God in prayer and petition is not to come in zealousness and piety but in humility and brokenness.
In Luke 18:13-14, Jesus says this about a sinner's prayer: "But the tax collector, standing far off, would not even lift up his eyes to heaven, but beat his breast, saying, 'God, be merciful to me, a sinner!' I tell you, this man went down to his house justified, rather than the other. For everyone who exalts himself will be humbled, but the one who humbles himself will be exalted."
Pray aloud to strengthen others' faith
Many times in scripture, praying aloud does have it's place. Jesus would pray aloud in addition to withdrawing for private prayer. Corporate prayer is a time when the body can motivate and edify each other up through prayer. When we pray for one another aloud, we build each other up in the faith by reminding each other of how faithful God is and by being a channel of God's faith too.
At the end of the day, it doesn't matter as much to God how you pray, and what He looks to most is having the humility of heart to approach God saying that He is the only way to see our prayers answered.