What makes a ballad work
Launch library · evergreen read

A ballad slows everything down quite deliberately. Tempo drops, arrangements thin out and the vocal is given generous room to breathe, all so that the emotional content of the song can be heard clearly rather than competing constantly with rhythm, volume or unnecessary instrumental noise happening around it.
Melody carries most of the weight in a ballad, often moving in longer, more deliberate phrases than an up tempo song would ever really allow. That patience lets small shifts in pitch feel genuinely significant, since there is comparatively little else pulling attention away at any given moment in the song.
The best ballads also resist the temptation of over decoration in the arrangement. Restraint, a piano, a few strings, a steady, unhurried rhythm, keeps focus squarely on the voice and the story, which is usually exactly where a well written ballad wants the listener's attention to remain entirely, undistracted by anything else.