How many of us had a mother who cajoled us to, "Stand Up Straight!"? As a speaker, listen to your mother.
It sounds deceptively simple. And it is. However, when you look at the act of speaking, posture is central to success. Standing erect helps with presence, pace, diction and volume.
So much of what we do nowadays works against a student's posture. Looking at SMARTphones, computer desks and terminals, and backpacks, its a wonder our kids can walk upright.
So, listen your mother. And it would hurt to call now and then, would it?