Methinks "good taste" refers not to the set of things you decide are good or bad, but to the perception and analysis you use to make such decisions.
It's best if you're able to explain yourself. The consummate person-with-good-taste-in-music should be able to listen to Led Zeppelin and say, "Ah, this is good, they do XYZ really well, those are the things that make this song good"; and it should be right, which means that if you took Led Zeppelin and had them do X not as well, and played the result to members of the general public, they would react much less enthusiastically than they would to the original song.
Being able to say "this is good" or "this is bad" is a start, but the really useful thing is to be able to go deeper and say "this is good overall; XYZ are good aspects of it; ABC could have been done better". 'Cause then you can tweak ABC and make it even better, or go to a comparable project and fix its XYZ.
It's sometimes possible to use your taste to be successful even if you're not able to explain yourself with words. If you're carefully listening to your project (or using whatever sense is appropriate; imagine a man closing his eyes and calmly giving his entire attention to the sensation), and you just feel that a certain thing isn't the way you like it and needs to be changed in a certain way, and you make the change, and repeat the process until you're satisfied... If you have very good taste, then these things that you felt needed fixing were precisely the things that the consummate person-with-good-taste would perceive and describe, and your product should now be really good (at least, much better than before).
If you have that kind of taste, and if you have control over your project (or if the people working with you simply trust your decisions), then you can get success without ever developing the ability to articulate just why a particular thing is good or bad. On the other hand, it is probably possible to have excellent taste in most regards but to just be flat-out wrong about a couple of important things. To guard against this possibility, it is useful to be able to explain yourself and to compare your words with others's.
You can probably start to learn to articulate your tastes by experiencing several things that are similar, but you definitely like some of them more than the others, and thinking about what makes them different and what might explain your preference. You'll have to be careful--not to attribute like or dislike to the wrong things--but you will probably make progress sooner or later.
See also "Blink", by Malcolm Gladwell.