Leading a congregation in prayer is a most important responsibility. When you are called upon to do it, you should try your utmost to do it right. To help you lead an effective prayer, this page points out some of the mistakes to avoid.
The model prayer that Jesus gave his disciples is short. It takes only 30 seconds to speak this prayer (Matthew 6:9-13).
Jesus warned against using "empty repetitions" (Matthew 6:7). Some prayer leaders pad out their prayers with meaningless churchy phrases. For instance, instead of saying, “Please keep us safe on the roads tonight”, they might say, “As we leave this place and go our various ways, we beseech Thee that Thou wouldst grant Thy children journeying mercies that they might safely arrive at their intended destinations”.
When you lead in prayer, speak for the congregation, not to it. It is not your task to reprove, rebuke, or exhort the church. Your task is to lead the church in a prayer to God. Preaching to God, and hoping the message will rub off on the congregation, is not a proper use of the ministry of public prayer.
If you want to combine 400 year old English with modern English, then study how it's done properly in a modern translation of the Psalms that retains some archaic forms in words addressed to God.
Be aware that public prayer is not the place to mention private matters.
In the public prayer checklist you will find other pointers for leading public prayers.