Unlike epic beginnings, ending a song is pretty damn easy. I’m not at all well-versed in musical theory, but to give you the basic understanding as I understand it most of western pop music based on the diatonic scale. True story, I have been using that scale for years without even knowing what it was called until I just looked it up a minute ago. Blues and early rock and roll uses a five note scale, but the principle is pretty much the same.
For the purposes of understanding each other, musicians will tell each other which scale a song is in based on the note that the scale starts with. This narrows down the notes we are able to play, and, in theory, if we stay in that scale, even if we hit the wrong note sometimes, we’ll sound at least not terrible. That note is usually where you want to end the song, because that’s just what sounds right. Why? That’s what your ears are trained to hear by every song you listen to. Beyond that I can’t explain.
Basically if you end on the starting note of the scale you’re using there is no real way to screw up the ending besides having your band not pay attention to each other and end at different times.
The Ramones She’s the One
Which makes it unnerving when a song doesn’t end on the note you’re expecting. This song is my favorite example:
I really like this song, but the ending is kind of off-putting and tense. But the whole song has an odd tension to it and I suspect that’s the way the writers intended it.
But other than ending on an odd note, there’s the classic hack producer ending, also known as the fade out-
Slade Gudbuy T’Jane
This makes the listener keep repeating the chorus in their head after the song is over. It’s cheesy, but I’ve used it.
A few people have improved/modified this by adding little extras at the end, like this
Tupac Can’t C Me
Tupac often used the end of his songs as mini-jam sessions. Or in the case of his legendary diss song Hit Em Up- as time to tell East Coast rappers what he really felt about them, in case they didn’t already know.
T-Rex 20th Century Boy
This one ends with something like
I’ve got a car that drives like a plane I wanna make it with you in the pouring rain OHHH YEAAAAH
Marc Bolan loved those. He sang something similar on Bang a Gong (Get it on) and some other songs that I can’t remember the name of at the moment.