Thanks, PT. I learn a lot about audio work every time I do a song, and I learned a ton on this one, even though I am very happy with the end result, there is a lot I will do different in the future. One thing I can say for sure is to get better at this sort of thing you have to just make songs over and over. I have so many crap throw-away songs that it isn't even funny. But they were all necessary jut to get good enough to even make this one that I'm starting to actually be pretty happy with. Oh, and if you hear something that you want to emulate . . . a specific instrument sound, effect or even a certain genre you're after, Google it. Read blogs and watch YouTube tutorials. The most significant overarching principle that I've discovered applies to getting any song to sound "popular" (or professionally mastered, however you want to put it), is that . . .
. . . even though it sounds like everything is blasting out all at once, it is not. Most if not everything is side-chanied to the drums so that the drums are the loudest thing in the mix every moment they hit, everything is equalized carefully so that each instrument occupies its own frequency range, and especially so as to stay out of the way of the bass.
If you don't do these things, once you get up much over five different voices/instruments going at once, it turns into an impossible volume war in which you run out of headroom.