Lighting: Make sure you place the light source in front of you and sit facing the light. Avoid placing lights above your height, as it may cause shadows under your eyes and nose. Check out yourself in the computer's camera, if the light is evenly spread.
Framing: Keep yourself centered in the frame. Maintain a comfortable arm's length distance from your computer. Make sure your head doesn't go beyond the top edge of the frame or have too much “headroom” (the space between the top of your head and the top edge of the video). Position yourself so that your eyes are within the top 1/3rd of the frame.
Sound: Shoot in a quiet area where there is NO background noise (no one on the telephone, AC noises, or background conversations). Remain within 3 feet (1 meter) of your computer at all times. Otherwise, the sound quality could be compromised.