Use the best Internet connection you can.
Mute your microphone when you're not speaking.
When your microphone is on, Zoom will devote part of your Internet connection to an audio stream for you, even if you are not speaking. Mute your microphone when you do not need it, and you will allow Zoom use your Internet connection more effectively.
Stop your webcam video when you don't need it.
If your instructor or moderator is okay with you doing so, start your video only when you need to show yourself on webcam, and stop your video when it isn't needed. Disable HD webcam video. Sending high definition (HD) webcam video requires more bandwidth than sending non-HD. Disabling HD video will free up more of your Internet connection for other parts of your Zoom meeting.
Close other, unneeded applications on your computer. Zoom meetings can demand significant memory and processing power from your computer. Closing other applications, ones you do not need during the session, will help Zoom run better.
Avoid other activities that will steal bandwidth. Don't start other bandwidth-intensive activities just before, or during, a Zoom meeting. On your Zoom device (or other computers and devices that share your Internet connection) avoid downloads, large uploads streaming video (e.g. Netflix, Hulu, YouTube), cloud backups, or other high-bandwidth activities.
Communicate with the instructor or moderator of your Zoom meeting. If the best Internet connection you have for Zoom is a slow one, such as a weak cellular data connection, let the person or people running your session know ahead of time. The instructor or moderator can determine if it is just best to call into the meeting.