So how do you know if your speech was effective? There's this attitude out there that public speaking is a so-called soft skill, like it's a little puppy. Like it's just this intangible thing. It's not a hard nose thing, like accounting, or chemistry. Well to that I say, "Baloney."
You can quantify your public speaking exactly the same way you do any aspect of accounting, or physics, or chemistry. How do you do it? Same way you do anything else. You test. You measure. If you had to give a presentation to thirty sales execs on Wednesday, give them your presentation. When you're done, ask them every message point from your speech they remember. Ask them every slide from your PowerPoint that they remember.
Any message point that they can throw back in your face, you now have empirical evidence that the way you presented that was effective. Any PowerPoint slide that they can remember, and toss back in your face, you have empirical evidence that the way you presented it was effective. However, if you ask them how you did and they say, "Oh, well. T.J., everything was great. You're a wonderful speaker. That was fine," then I know I was awful. I know I failed. I know I bombed.
So it's very easy to find out what's effective, and what isn't effective. Now, here's the secret. You don't have to wait until you get in front of your real audience. If you're speaking to fifty clients on Thursday, find three colleagues together Tuesday, at lunch time. Give them a free sandwich at lunch. Give your presentation. When you're done, ask them every message point they remember. And if there's something they don't remember, you've got to go back and retool your presentation, and do it again, until they remember.
This is not touchy feely. This is not squishy. This is not "Hmm, I wonder if the room was warm that day?" This is quantifiable. You can find out if your speech is effective or not. You're either remembered by your audience, or you're not. It really is that simple.