Elocution expert Richard Ellis says plenty of water and learning to breath properly helps people with their delivery.
He also urges ministers to learn poetry, keep scrap books and wear loose clothing.
He's passing on his wisdom as he leaves his role at Edinburgh University's School of Divinity (New College) after 35 years of helping those training for ministry.
During his time in the job, he's critiqued 800 sermons – the equivalent of 16 years of talks.
He says the approach of ministers has had to change over the years.
"I quickly discovered many ministers had been taught how to convey meaning through a range of sweeping arm movements and hand gestures," he said.
"That may have been useful when addressing very large congregations, but times have changed.
"There may be fewer people in the pews now, but often the minister is addressing more people who are watching the service online through a webcam so the techniques have to be different."
His sessions with trainee ministers have included everything from learning to keep eye contact while preaching to how to structure a sermon.
For those enetering the ministry now – he's encouraging them to look at how President Barack Obama delivers speeches.
"He's a master at the use of pause," said Mr Ellis.
"If you want to pose a rhetorical question in your sermon you have to pause."
Richard Ellis speaking to Premier's Aaron James: