I've recorded more than 100 videos using my webcam. Here's what I've learned:
1. Webcam positioning should be around eye level
2. If you're on a budget, use natural light and make sure the webcam is pointed away from the sun
3. Don't rely on built-in microphones; at the very least use your mobile earphones
4. Download the manufacturer software to adjust your webcam settings and get better visual quality
There's other tips and equipment recommendations in this video: