Become a musicianbecoming a musician changed my listening experience more than anything ever has
the more i played, the more sound types i and others around me experimented with, the more i started noticing different sound qualities, and preferences.
after playing for some time, recording albums in a studio also majorly honed my listening skills
hearing crappy instruments, getting used to them, and than trying a high end instrument, the difference is amazing... over time hearing so many different styles and qualities of instrument, amp, strings, mics, woods, metals, builds etc... your ability to differentiate develops substantially. Especially if you have an equalizer on your instrument, then you really start dialing in all kinds of sounds.
After a couple years i started finding that i could hardly listen to certain albums, or especially certain bands perform live because the sound quality or mix was so poor.
when i first started playing bass, i couldnt tell one instrument from another, after a few years, i could tell you what frequencies on the equalizer i needed to adjust and how the sound would change without looking, i could tell you what type of wood someones instrument was made of by hearing it. I started adjusting my eq to compensate for string wear... i could hear the difference between a bolt on and a neck through construction...
thats my advice.. become a musician... :-)