Lighting and Sound
Good lighting will help you communicate more effectively and appear more professional. In general, more lighting allows your video camera to transmit a clearer image of you.
Avoiding Backlight
Backlight refers to light that comes from behind you and points toward the camera. Since the light cannot reach your face effectively, your image may appear as a vague, dark silhouette with a bright background.
To present a more balanced image, turn the camera away from windows, lamps, overhead lights, etc. This will force the light to reflect off of you, creating a higher quality picture.
Camera Settings
Check whether your camera can be adjusted to overcome low light, backlight, or other poor lighting conditions.
Eliminating Echo
To avoid an "echo" effect caused by your microphone picking up sounds from your speaker, turn your speaker volume and microphone volume as low as you can without losing clarity.
Alternatively, using a headset or echo-canceling microphone can also eliminate the echo.