Once you’ve got your gear in order (microphone(s), camera or other filming device, tripod and phone holder, lights, mirror, instrument(s)) there are some general rules that will give you better results.

CAMERA ORIENTATION
A lot of you will be using your smart phone as your camera, and that's certainly a viable option since the rear facing camera (the one on the back of your phone) is usually pretty high quality. If you plan to use your smart phone, regardless of anything else that you do, please, hold your smart phone horizontally, so that the image is wider than it is tall, and it can fill the screen on a laptop/desktop/tablet. That said, read on...

CAMERA QUALITY
The better your camera, the better the video. If at all possible, use a DSLR, a quality webcam, or the rear facing camera on your smart phone or tablet. (The front facing camera on your device records much lower quality video.)

NOTE: To use the rear facing camera, you can reflect enough of your devices’ screen in a glass mirror to insure that you are ‘framed’ the way you intended. Or you can use screen mirroring to a TV or monitor, if that’s available.

USE YOUR DSLR AS A WEBCAM
CANON
In April 2020 Canon released their free EOS Webcam Utility Beta . a utility that allows a large range of Canon cameras to be used as a webcam on both a Windows or a Mac platform.
This can be a real game changer because it allows the direct connection of your camera to your computer through a USB connection. This means no more need for an HDMI to USB capture card that can cost hundreds of dollars. This utility is still in Beta, so some of it's limitations (like not working with Skype) and a growing camera camera compatibility list are changing with each new release. Here's a YOUTUBE VIDEO on the utility.

NIKON
According to Nikon, this method is ideal for those seeking a high quality video stream with the simplest setup and no additional hardware.

- Connect your Nikon camera to your computer using the USB cable that was included with your camera.

- Download and install any third-party conferencing/broadcasting software that is compatible with both your Nikon camera and your computer’s operating system.

- Software like Ecamm Live (Mac), Vmix (PC), SparkoCam (PC) have compatibility with select Nikon cameras via USB and can seamlessly connect to streaming applications like Zoom, WebEx, Twitch, Facebook Live and others.

VERY IMPORTANT
No matter what recording device you’re using, clean the lens before you start recording.

RECORDING QUALITY
You should always be filming with your camera in the horizontal position. That way your videos will fill a 16:9 screen and allow for the most flexibility in post production.

If there are quality choice available, always choose the highest quality available, although 30fps is fine for performance videos (you don’t need 60fps and it will make your file very big).

If the video format is changeable, it should be set for 1080p (1920x1080 pixels ) using an mp4 container with an h264 codec, and a frame rate of 30 frames per second.

If there are changeable audio settings, you should be recording 16 bit audio at 48 kb/s and 384kbps with an AAC codec.

If Video and Audio formats are fixed, or you’re not comfortable changing them, they’ll probably default to something usable.

RECORDING SPACE
Most of us don’t pay a lot of attention to the space available for storing recordings on our devices. Make sure that you have enough space available for your videos. As a rough guide, you’ll need about 128mb for a 1 minute recording (1GB of free space will hold about 8 minutes of 1080p video)

USE A TRIPOD
Set your camera on a tripod and make sure that you frame the shot to your liking. There are no hard and fast rules, but normally you’ll want horizontal lines to be horizontal and vertical lines to be vertical.

WHITE BALANCE
White balance is the process of removing unrealistic color casts, so that objects which appear white in person are rendered white in your video. Most cameras can use their automatic (or manual) white balance control to do a pretty good job of adjusting the White Balance for a single lighting color, however, it’s important to understand that white balance can only adjust for the overall color in your shot, and cannot adjust for multiple individual colors.

AIRPLANE MODE
If you’re using a tablet or smart phone, put it in ‘Airplane’ mode. That way you won’t be interrupted by unwanted notifications or calls during your recording.

MANUAL EXPOSURE AND FOCUS
Most cameras are set by default to automatically adjust for changing light levels and focus while filming. This can lead to very strange results when, for example, a dark object moves around in the frame or you or your instrument moves around and the camera continually tries to re-focus.

Set your camera to manual exposure (AE lock) and manual focus whenever possible.

LIGHTING
In general, webcams and smart phone cameras react better to relatively bright, even overall light in addition to any other lighting you're using. DSLRs are more forgiving of high contrast ‘creative’ lighting.

Be careful of harsh shadows, and use ‘fill’ lights to make them softer.

WINDOW LIGHT
If you rely on the light from a window as your main source of light, make sure that the light won’t change during your recording session due to clouds or time of day. And, don’t film in harsh sunlight that’s coming through the window. That will create harsh shadows in your video. Besides, the shadows will move over time. Another thing to be aware of is the color of the light caused by reflections outside the window. Grass will make the light green, a large orange building can make the light look orange.

That said, the closer your light is to a ‘daylight’ lighting color, the more natural your video will look (especially in skin tones). The more control you have over the lighting in your shoot, the more consistent your results will be.

ARTIFICIAL LIGHT
Each type of light has its own ‘color cast’. While, daylight is slightly blue, incandescent bulbs give off a yellow light, and non-daylight florescent bulbs give off a yellow-orange light. Both Florescent and LED bulbs are available in ‘daylight’ colors.

If your main source of light is a window (natural light), and you use tungsten lights to fill in shadows in your shot, the camera will not be able to set an accurate white balance, and things like skin tones will suffer.

STUDIO LIGHTS
The most control over the look of your video can be accomplished by using studio lights. Using studio lights doesn’t have to be a daunting, or expensive process. Studio Lights just means that you are using artificial lights to light your ‘set’. The most pleasing results will be obtained by using soft light, that tends to "wrap" around objects, casting diffuse shadows with soft edges. Soft lights can be DIY affairs made from white sheets hung in front of light fixtures, or from cardboard boxes painted white in the inside with tracing paper in front of them, or they can be purchased on Amazon and from a number of other sources. They can be used alone, or to augment existing room lighting.

.Here are some links that might help

Tips for Setting Up a Home or Office Studio (overkill but some good ideas)

20"X28" Soft box Photography Lighting Kit

TEST
Before you do the actual filming, it’s a good idea to make a few short tests, and if at all possible, play those tests back on a large screen using at least good quality headphones or earbuds. It’s very hard to determine video quality, focus, etc. on a small smart phone screen.

ACTUAL RECORDING
Before you break down your recording setup, play back your video (again on a large screen using at least good quality headphones or earbuds) and make sure that you’re happy with the result.

You’re, a professional musician, and you’re competing with all the other performance videos out there. It’s not important that you produce a complex music video, but you’ll want to be proud of the finished product you create.