Flickering is often a result of the desynchronization between the shutter speed/frame rate of the camera and the frequency of the AC power that the lights are plugged in to.
1. Adjust Shutter Speed:
One solution is to use a shutter speed/frame rate that is slower than the AC power frequency.
For example, in the U.S., AC power is 60 cycles per second, so try shooting with a frame rate lower than that - 30 fps, 29.97 fps, 24 fps, 23.98 fps - and a shutter speed slower than the AC power frequency.
2. Use Natural Lighting:
Whenever possible, use natural light sources to avoid conflicts with artificial lighting.
3. Use Continuous Lighting:
When using artificial lighting, choose continuous light sources instead of fluorescent or incandescent lights. Continuous lighting provides consistent light output and minimizes flicker.