Always do “the Scratch Test” before hitting record.
Check to make sure whatever software, service, or device you are using has picked up your microphone.
If you are interviewing someone over the internet, ask if they can hear you scratch the top of the mic. If they can… GREAT! Now ask them to do the same.
If you can't hear the scratch, then have them check the settings.
Do this EVERY time you sit down to record.
Oh, and make sure you press the “RECORD” button.