Set your camera to be at eye level. The camera should not be looking up or looking down at you as the speaker.
Ensure that the camera is steady and level.
The camera should capture a bust shot. Please see the below figure as an example.
Ensure that there are no bright lights behind you. Most cameras cannot produce decent images if there is too much light behind you.
Ensure that the bulk of the light is directly in front of you. Avoid lighting that is coming at an angle, as that can cause shadows on your face.
Ensure that the background is as plain as possible. A white wall or sheet is best to prevent any attendee distraction.
Test, test, and test! Most webcams are set on auto, which is a good start. You may want to take your webcam off auto and make manual adjustments to various settings such as brightness. This will help to keep the camera image constant to avoid any automatic dimming or brightening while you are recording.