The AAMC has published an Applicant Preparation Guide with a variety of helpful ideas for interviewing virtually during this pandemic, and I certainly recommend reading it carefully. I also have a few additional suggestions:
1) If you're using your laptop, get an Ethernet cable to plug it directly into the router, instead of using Wi-Fi. The signal strength is much stronger and more consistent when using a physical cable! That's what I have, and this is the most valuable suggestion I can make. (also ask other people in your home to avoid using the internet during your interview, if possible)
2) Good lighting helps, as does the location of the lighting. Depending on how your room is set up, you might consider moving to a different spot to take advantage of (or avoid) light from the window. You can also put a small lamp on your desk.
3) Spinning fans directly overhead can be very distracting, and also use up bandwidth as your computer tries to process the image. Also, consider what else might be visible behind you during a virtual interview.
4) If your laptop is an older model with a low quality camera, you should consider investing in an external webcam.
5) There are settings within certain programs that might enhance your use of a high definition camera, if you have one. For example on Zoom you would go to the settings, then click "Video" and finally the checkbox for "HD". However, this uses more bandwidth, and can paradoxically make your connection worse, so test it with a friend in advance.
The AAMC guide has much more information than what I just wrote above, so please read it carefully; I just wanted to supplement it with some other ideas. Good luck!