A brief excerpt from a TJ Walker live stream where he advises speakers on microphone choice and practical handling. He discourages handheld microphones because they restrict gesturing and can evoke a stand-up comedy style; he recommends lavalier (clip-on) mics or wireless handhelds when necessary, and offers hand-gesture and hand-switching tips to avoid volume swings.
Chapters
What is the most effective way to use one of these when you're giving a speech or presentation? A handheld mic. Now, in general, I try to avoid handheld mics because it instantly shuts down your ability to gesture. So you're closing down basically half your body language. The other problem with holding a microphone when you speak is to me, it is too similar to the image of a stand up comedian, because stand up comedians do this because they want to whisper and they want to use the full range of their voice for comedic effect in the way most speakers don't. So I don't recommend that you have a handheld mic. I recommend that you have one of these, a lav mic that just clips on a part of clothing, whether it's a jacket, a tie, a shirt, a blouse, or sometimes you see the more showy Hollywood ones. Those are fine too, as long as they don't attract too much attention. But let's face it, you can't plan for every single speaking opportunity 100% the way you want. Or you can try to, but you might not get it. So there are times when you're going to get a handheld mic. If you're going to get a handheld, far better for it to be one that is wireless, so you don't have to worry about the wire. My recommendation when you're using a microphone is gesture with your other hand and occasionally change hands. The problem some people have is they start gesturing like this and all of a sudden their volume is going to go way up and down, wildly distracting. You cannot move your hand when you are holding the microphone. Not an effective thing to do at all. Keep these tips alive in your mind and you'll be a better speaker.