Music dictates how the viewer feels. If the music doesn't match the script, the viewer will feel a "disconnect" and scroll.
Trending Audio vs. Originality
Using trending audio is great for the algorithm, but original, niche-specific music is better for brand building.
Beat-Syncing
The visual cuts should happen on the beat of the music. This creates a "satisfying" viewing experience that keeps people hooked.
Volume Levels
The voiceover should always be at least 10dB louder than the background music.