You can just run through the major scale in your head. Most people can just sing this naturally. Then you give each note a number. So, for example you can start on a note and sing DO, RE, ME, FA , SO, LA. LA is the 5th. Learn how to tell the difference between a major 3rd and flat (Minor) 3rd and now you have that under your belt. Also certain types of music rely on certain chords. Like Dominant 7th chords with a flat 7 are used in blues all the time. Pop songs use mostly basic 1,3,5 chords so when you hear something different about it then you can estimate it as a more colorful or developed chord ike a Major 7th. Diminiished chords are very easy to hear. Anyway, if you want a more in-depth discussion we can all schedule a zoom meet up. Just let me know. 😁

I just realized the question was for a different kind ear training. Lol. I guess I spent to many hours on the other side of the glass. lol