How do you mentally prepare for your presentation?

One of the quotes I use when I am working with people to identify and get into the right mental state for presenting is this one:

All things must be mentally accomplished first before they are physically accomplished.

This vlog explores how to do this.  It looks at visualising successful outcomes and mentally rehearsing delivering a presentation before you deliver your presentation. It also means sharing with people what successful outcomes will look, sound and feel like in the presentation so that they are ready to physically accomplish your request. 

What is your favourite quotation and how does it impact on how you work?