Try listening exercises;
Listen to a song, and try and identify every instrument in the mix.
Try selective listening, meaning try and pick out just the bass line, just the rhythm guitar, just the piano....Oh yeah and just the drums. Try and pick out the bass drum by itself. Then the hi hat or ride. Then the snare. You get the idea.
Try and pick out the background stuff, not the out front stuff. The out front stuff is easy usually.
Try and understand what part of the song you're listening to. You should always know this, you're the navigator of the song. Are you listening to a verse, chorus, bridge, pre-chorus, into, outtro, breakdown, ornament (a one time thing) solo, or whatever.
Once you break songs up into verses, choruses bridges et al, it makes it easier to understand. One whole song is made of a few different parts, in a certain chronological order, which I call the arrangement. Like when I make my own little charts, I write down intro/ verse/verse/chrous/solo/bridge/verse/chorus/ending. Except I abbreviate it. Sometimes I notate the bars of each part if I'm not familiar with the song. I also write what the bass drum pattern is, 1/4's 1/8's or 1/16th on the ride or hi hat, what time sig, where the back beat is, and anything else that will jog my memory about the beat. I don't write tempo down, I remember the feel, but that's helpful too.
Listen with a purpose. Decode the song, divide and conquer.