The key is to look directly at the camera lens. While it is tempting to look at yourself talking (depending on the camera and webcam in use) or focus on different spots throughout the video, your audience is only right in front of you. Take heed of the limited space of the camera.
What Sells Best On Shutterstock?
Some types of photos that sell best are Portrait Photography, Food Photography, Landscapes (usually with people) and fine art photography (artsy).