In order to avoid audio feedback during your web conference, adjust the position of your microphone and headphones/speakers to get the best sound. Ensure that your speakers are far enough from your microphone, to prevent any audio looping. If you are using a headset mic and earphones, ensure they aren't blocking your face, as this will help prevent muffled sounds. Furthermore, try your best to avoid moving things around or shuffling through papers while you or others are speaking. Lastly, turn off TV's, radios and other electornics to further eliminate background noise.