What a great privilege you have to preach the Word brother, and what a wonderful desire that is to preach on prayer!
While there are many verses and biblical stories/models for prayer I would like to share a few that strike me.
In 1 Timothy, Paul is writing to Timothy and makes the purpose of his letter known in the below passage from chapter 3:
"14 These things I write to you, though I hope to come to you shortly; 15 but if I am delayed, I write so that you may know how you ought to conduct yourself in the house of God, which is the church of the living God, the pillar and ground of the truth."
He clearly is saying that he is writing so they "ought to know how to conduct themselves in the house of God, the Church". What kind of conduct should the Church have? What should define it? What ought meetings of the Redeemed to look like? If you rewind to chapter 2:1 when he officially started laying out the groundwork for Church gatherings, what does he start with?
"2 Therefore I exhort first of all that supplications, prayers, intercessions, and giving of thanks be made for all men,"
The very FIRST thing mentioned is prayer - this is central, this is preeminent, this is supreme.
I believe this would be a good starting point to help the Body see the emphasis and importance of the Body coming together in prayer in a corporate setting.
I visited a church a few weeks back and while they were showing me around to the children's ministry classes and describing all of the events of the church I inquired, "tell me about the prayer meeting, when does the church meet for prayer" the girl who was hosting the information counter said "hmmmm I think that was happening on Monday nights but I am not sure if it's still going on." I asked another young man after service the same thing, and he said, "oh yes we have a prayer team who can cover requests". It made me very sad. Perhaps i was reading too much into the situation, but I fear that churches have "prayer teams" that supplant the congrgational prayer meeting. Why does the Church need to come together for prayer when there is a designated prayer team to do all of the praying? I am all FOR prayer teams, but may it truly not be that they are in place of the call from the pastor/elders for the church to gather as one in corporate prayer and seeking of the Lord together before the throne.
One final passage that is beautiful for intercession is Numbers 16. Read the whole chapter and place it in context, and especially the passage below where Aaron the Priest intercedes with fire & incense and stops the plague. It says he stood between the dead and the living - I don't think you get a better picture than what prayer is meant to be in intercession.
"46 So Moses said to Aaron, “Take a censer and put fire in it from the altar, put incense on it, and take it quickly to the congregation and make atonement for them; for wrath has gone out from the Lord. The plague has begun.” 47 Then Aaron took it as Moses commanded, and ran into the midst of the assembly; and already the plague had begun among the people. So he put in the incense and made atonement for the people. 48 And he stood between the dead and the living; so the plague was stopped. 49 Now those who died in the plague were fourteen thousand seven hundred, besides those who died in the Korah incident. 50 So Aaron returned to Moses at the door of the tabernacle of meeting, for the plague had stopped."
God bless you brother - may the Lord stir the fellowship you are speaking at to receive the Word the Lord gives you! Be faithful in the sowing and God will give the increase!