Here is an amazing prayer for all preachers to pray, and for those who pray for preachers to adapt to the third person. It's taken from The Valley of Vision which is a collection of Puritan prayers. This prayer is called "A Minister's Preaching" on pp. 348-349 in the leather edition printed in 2002.
MY MASTER GOD,
I am desired to preach today,
but go weak and needy to my task;
Yet I long that people might be edified with divine truth,
that an honest testimony might be borne for thee;
Give me assistance in preaching and prayer,
with heart uplifted for grace and unction.
Present to my view things pertinent to my subject,
with fullness of matter and clarity of thought,
proper expressions, fluency, fervency,
a feeling sense of the things I preach,
and grace to apply them to men's consciences.
Keep me conscious all the while of my defects,
and let me not gloat in pride over my performance.
Help me to offer a testimony for thyself,
and to leave sinners inexcusable in neglecting thy mercy.
Give me freedom to open the sorrows of thy people,
and to set before them comforting considerations.
Attend with power the truth preached,
and awaken the attention of my slothful audience.
May thy people be refreshed, melted, convicted, comforted,
and help me to use the strongest arguments
drawn from Christ's incarnation and sufferings,
that men might be made holy.
I myself need thy support, comfort, strength, holiness,
that I might be a pure channel of thy grace,
and be able to do something for thee;
Give me then refreshment among thy people,
and help me not to treat excellent matter in a defective way,
or bear a broken testimony to so worthy a redeemer,
or be harsh in treating of Christ's death, its design and end,
from lack of warmth and fervency.
And keep me in tune with thee as I do this work.