https://www.youtube.com/watch?v=KlJAiwwGHMg

a lot of people probably have already heard it, but love the vocals on this.

Hi guys, I didn't grow up playing any instrument or learning any music theory. A method to finding the key a song is in, for me at least, is opening up your DAW with a basic piano synth. Then while you are playing the song, during a melodic part, if you simply play each of the keys in the musical scale one by one, there will be a key (the tonic key) that sounds good anytime you play it, The other keys wont sound as well, besides the exception of 2 that will fit ok, but not as strong as the tonic note. You can check how you did by looking up the key of the track on a website such as beatport after.

If anyone has a method to identify these things by ear to share that would be cool, the only way I can do it is by trying notes on an instrument simultaneously while the song is playing.