These are some of Martyn Lloyd-Jones' thoughts on how we should pray in public prayer meetings. These things are taken from the book "Memories of Sansfield" by his wife Bethan Lloyd-Jones.
We should not be too personal, but remember that whoever is praying is leading all of the congregation to the Throne of Grace.
'It would be better in the public prayer meeting not to make mysterious references and ask God to "bless that person I spoke to yesterday, who was in such trouble." and so on, It isn't necessary and it breaks people's concentration on their prayers, while their minds go wandering off, wondering who that person was!'
Don't make long prayers. Many people want to pray and we must not be selfish with the time.