When I’m asked about the secret to good public speaking, my first instinct is to respond, "It's a journey you take the audience on, both intellectual and emotional, involving both content and delivery, and it’s a complex process, an art form, involving lots of moving parts." 

But if I'm pressed for one rule only, it would be this:  have fun. 

That's right — have fun. 

Could it possibly be that simple? 

Audiences have provisionally given up their authority and bestowed it on the speaker.  They want the speaker to succeed.  Otherwise, they've wasted their time, and who can afford to do that these days?  The best thing the speaker can do is to signal to the audience that he or she is having a good time.  It will let the audience know that it is in good hands.  It can relax and enjoy the experience. 

That creates a virtuous circle — happy audience, happy speaker — and those good vibes go a long way toward creating a good experience for all. 

Of course, the hard part about having fun is that most people are nervous when they speak, at least at the start.  So how do you relax and have fun when your heart is hammering away, your palms are clammy, and you're thinking to yourself, I will never, ever agree to do this again?

Focus on the audience.  If you can stop thinking about yourself, and start thinking about the audience, you've got a chance to begin to enjoy yourself.  Remember, a speech is not primarily about you, the speaker.  It's about whether or not the audience is moved to action. 

So relax, forget about you, and have fun.