Interesting ... And yet the easier, deeper states and practices are missing ... Though i do not mean this as a critique. As these easier deeper states are generally ignored within business circles.

The most fundamental is Breath. Where is it? What is it doing? If you find your breath is shallow or very rapid just before you are about to speak, you are in trouble. As no matter what you say in that state the overall impression will be of lack of confidence and lack of self-belief. So, deepen the breath. Long slow exhales are best. If a quick reset is necessary, exhale and hold the breath until a little beyond first signs of discomfort. If the mind is racing like crazy, go for a 4-4-4-4 cycle (each component of the breath cycle performed or held for a count of 4). If you have experience do them at 5 or 6.

Breath would sort most other issues but if Body is not feeling comfortable, shake it off. Even if it is hidden in getting up from the chair and kind of adjusting posture/clothes.

Very important when standing is to feel as if you are lifted by the centre of the chest (heart-led). A variation of this I heard from the Voice Coach to the London Olympics Delegation for the previous Olympics when they were putting their candidacy first and had to make their presentation. It changes your whole presence. It also changes the quality of the voice.

Feel your Passion for your work or for what you are sharing. In a roomful of well-rehearsed lines, that raw passion will make you stand out big time.

etc.