It's sad to admit this, but crappy, generic music has it's place: advertising.
I'm interning at a production house right now, and they have a wall that's simply filled with stock CD's. CD's with generic, boring, short clips of music that they use for television commercials, or sometimes even tv shows. The people/person that writes this music gets royalties every time it's used, and every time it airs. So yeah, write your generic music, make 3 or 4 versions of it, a full version, a 60 second version, a 30 second version, and a end clip for sudden endings, or if the people working with it want to end it earlier. Do this for a bunch of tracks. Sell it as music for advertising (through an agency, of course, you can't just sell it on the street).
What I'm saying is, that kind of music has it's place.
The more avant-garde stuff has it's place too, you just have to find the market for it. Getting picked up by a label is an outdated, and now almost non-existent ideal.
To be successful in music today, you have to have numerous marketable skills, and be willing to think outside the box, maybe even create a market where there previously was none.
ex. Are you a composer who is just starting out, trying to get your pieces played?
Don't write orchestral music. It's bulky, and good luck finding 50+ musicians that want to play it.
Don't write piano music, there's enough of that. (Unless it's educational, that might work, you could sell it as an instructional publication)
Instead, write a piece for french horn, oboe, and tuba. That's a strange group, right? There's only 3 musicians you need to find, and it will gather interest because people will be like "What? French horn, oboe, and the tuba? What an odd pairing, I wonder what that sounds like." People already know what a piano piece sounds like. People already know what a orchestra piece sounds like.
But to actually answer your question, good music to me is what sounds good to me, and to hell with other people's opinions. Yeah, that's a dangerous thing for me to say, and contradicts what I said earlier, but the simple truth is that music is music. Some people may not like it, some people will.
But if you yourself aren't happy with your work, try working a different way. Try playing your music in instead of consciously transcribing it in some notation software. (Give Logic a try) Listen to music you normally wouldn't listen to, and try to find something you like about it. Review your music theory. I dunno, do SOMETHING. Just don't give up on it.
I expect to be working on the side, and not JUST composing when I'm done with college. I'll probably teach composition or theory at a private school, or in college (no certification needed), give instrument lessons, do transcription, publishing, maybe even a little design. I'll definitely work in a production house on commercials, but probably won't be using my own music on them because it's cheaper to use crappier music. I'll be utilizing the various technical skills and software/hardware know-how I've developed from going to school here at Duquesne.
I'll be writing on the side, every single day. Maybe I won't start getting commissions, or serious money from JUST composing until I'm 30, maybe not even until I'm 50, but the day WILL come if I keep at it, and keep writing, and continue to hone my compositional craft.
And I'll be enjoying myself the whole time.