Before you speak.
A DIFFICULT CONVERSATION
"I need to raise [issue] with [who]. Here is what happened: [facts]. Help me structure this so it is clear and fair."
ANTICIPATING THE OTHER SIDE
"What might they say? What would a reasonable person in their position think?"
Uncomfortable and useful.
A NEGOTIATION
"I am negotiating [what] with [who]. My position: [what]. What are their likely positions, and what should I be prepared to concede or refuse?"
Decide your limits beforehand.
A PITCH OR PRESENTATION
"I am presenting [what] to [audience] in [duration]. They care about [what]. What should I cover, and what will they ask?"
AN INTERVIEW
"Here is the job advert. What are the ten most likely questions? Then ask me each one and tell me what was weak in my answer."
WHAT NOT TO DO
Read from a script.
Prepare the substance and speak naturally.