Mics come in several types. The first clips to your lapel or collar. It has a battery pack, which you wear at your waistband, A lapel mike lets you speak normally, with the same amount of volume and vocal projection you would use to address a small group. The amplifier will do the rest.
A mic can be attached to a stand or podium. You don’t need to eat it. It’s designed to pick your voice up from up to 30cms away so don’t hunch over it, lean into it or alter your body shape to get your mouth closer to it. You should speak OVER these mikes, not into them.
You might have a hand held mic. The rules are the same as for mics on a stand. Keep it 30cms away from your mouth. Holding something in front of your face like this may feel awkward, but it mustn’t sag down to waist height – at least not if you want to be heard. If you have notes you need to be able to hold them in the other hand, and out to the side.
With this type of microphone, popping can be a problem. Popping is caused when "plosives" like 'p','t', and 'd' are spoken and the air from your mouth hits the mic. To prevent popping, position the mic about a hand’s width away and slightly below your mouth so that the air from your mouth does not hit the microphone. Blowing in any microphone (including your mobile phone) can damage it, and really hurts the ears of the listener. You may have experienced this if you try to use your mobile phone outside in the wind.
Mics can screech and whoop and give you feedback that completely ruins the experience for you and those listening to you. If you have rehearsed in advance, you should have a feel for how the mic is best positioned to avoid this. If something does go wrong during your presentation, wait for the rescue party – the IT person or the sound engineer. They can sort it out. Then calmly start again. If time is pressing or it can’t be fixed for any reason, switch it off, step aside, and just speak up.