Try to ensure your voice is already warmed up. If you bought a Bronze Pricing Pack or more then you will have access to the warm up tracks in the Member's Area and they are an ideal tool to help you with this.

Ensure you have a backing track for the song you want to sing and if possible, be familiar with the track so that you can skip to specific time stamps of lines/verses/choruses.

Try to have a device to play your backing track that is separate to the streaming device, but place it near that device.

If possible, have the streaming device similar to head height; avoid constantly looking down at the screen when singing.

If you have access to an audio interface with a microphone, then use it for getting better sound quality during the call. 

On your streaming device, try to ensure the noise suppression features of the Zoom are turned off (see right for how to do this on a  mobile device)