The one piece of advice I have given all of them is this: "Rehearse! Rehearse! Rehearse!" I give this advice because no one taught it to me; I had to learn it the hard way. When I first started learning public speaking in a Toastmasters club, I was locked to the lectern. I was so nervous that I grasped the sides in a white-knuckle death grip and read my speeches from notes.
Neuroplasticity reveals that our brains remain remarkably adaptable throughout our entire lives, allowing for continuous optimization of cognitive function.