what it takes
A well written song is comprised of many elements that all work together to strengthen it’s universal appeal with live, radio, television, and / or internet audiences.
It will also often adhere to certain guidelines that make it coherent from a technical standpoint musically, as well as in regards to following rules of grammar, language, vocabulary, prosody, and of course, current industry trends.
There are even ways to break all the theoretical, structural, and commonplace rules in a controlled mindful way.